Roasted Acorn Squash Soup with Crisped Duck and Rosemary
Acorn squash roasted until the cut edges caramelize, blended with leek and bone broth into a thick soup, and topped with slices of crisp-skinned duck breast.
Why You'll Love This Recipe
This is the soup I start making the week the mornings turn cold, and it is the one I hand to anyone who has been eating the same three vegetables since their elimination phase started. The squash roasts by itself for forty minutes while you get on with something else, and that is the only part that asks for real time. It carries to work better than almost anything else I cook, because a thick soup in a jar reheats evenly and never separates on you. I make it on a Sunday afternoon with the oven already hot from something else, and by Wednesday I am still glad there is a container of it in the refrigerator.
Two things keep this from tasting like blended squash. The first is roasting the halves cut side down, so the sugars in the flesh caramelize against the hot pan rather than steaming themselves pale. The second is the duck. Score the skin, lay the breasts in a cold dry skillet, then turn the heat to medium, and over about ten minutes the fat renders out slowly while the skin goes thin and crisp. That rendered fat is what the leeks and the rosemary soften in, which means the duck runs through the whole pot rather than sitting on top of it as a garnish somebody added at the end.
A puree on its own does not hold most people until dinner, which is exactly why the duck goes back on in slices rather than into the blender. You get the smooth spoonful, then a piece of meat with a crisp edge, and the two of them together eat like a lunch instead of a starter. The tablespoon of cider vinegar at the end is the step people skip and then wonder about, since a sweet squash puree with no acid in it tastes flat by the third spoonful. Chives over the top, a little of the reserved duck fat spooned across the surface, and the bowl is finished.
Ingredients
- 2 medium acorn squash (about 2 1/2 lb total), halved and seeded
- 2 boneless duck breasts with skin (about 1 lb 2 oz total)
- 2 large leeks, white and pale green parts only, halved and sliced (about 9 oz trimmed)
- 4 cloves garlic, thinly sliced
- 4 cups chicken bone broth
- 3 tbsp olive oil, divided
- 1 tbsp finely chopped fresh rosemary
- 1 tbsp apple cider vinegar
- 3 tbsp chopped fresh chives
- 1 tsp fine sea salt, divided
Instructions
- Roast the squash: Heat the oven to 425°F (220°C). Halve the acorn squash from stem to tip, scoop out the seeds, and rub the cut faces with 2 tablespoons of the olive oil and a quarter teaspoon of the salt. Lay them cut side down on a sheet pan and roast for 40 to 45 minutes, until a knife slides through the skin with no resistance and the cut edges have browned. Let them sit until they are cool enough to handle, then scoop the flesh away from the skin.
- Render the duck: While the squash roasts, score the duck skin in a crosshatch about a quarter inch apart, cutting through the fat but not into the meat. Season both sides with a quarter teaspoon of the salt. Lay the breasts skin side down in a cold dry skillet, set the heat to medium, and let them render for 10 to 12 minutes, pouring off the fat into a bowl as it collects, until the skin is deep brown and thin. Turn them and cook 3 to 4 minutes more, to 135°F (57°C) at the thickest part. Move to a board and rest for 10 minutes.
- Soften the leeks: Return 2 tablespoons of the rendered duck fat to the skillet over medium heat. Add the leeks, the garlic, the rosemary, and a quarter teaspoon of the salt, and cook for 6 to 8 minutes, stirring often, until the leeks are silky and smell sweet. Do not let them brown, since the whole point of this step is soft sweetness underneath the squash.
- Simmer: Scrape the leeks into a soup pot with the scooped squash flesh and the bone broth. Bring it up to a simmer over medium heat and cook for 10 minutes, breaking the squash apart with a spoon as it goes, until everything is falling into the liquid.
- Blend until silky: Blend the soup completely smooth with an immersion blender, or in a countertop blender in two batches with the lid vented. Give it a full 60 to 90 seconds, longer than feels necessary, and pour in the last tablespoon of olive oil while the blades are running. Return it to the pot, stir in the vinegar and the remaining salt off the heat, and thin with a splash of broth or water if you want it looser.
- Slice the duck and serve: Slice the rested duck across the grain about a quarter inch thick. Ladle the soup into bowls, fan the slices across the middle, scatter the chives over the top, and spoon a little of the reserved duck fat over each bowl.
Variations
- Roasted garlic: Roast a whole head of garlic alongside the squash and squeeze the soft cloves into the pot before blending for a rounder, sweeter base.
- Bacon on top: Crisp four slices of bacon, crumble them over the bowls, and use the bacon fat for the leeks when you would rather not buy duck.
- Less sweet: Swap a quarter of the squash for peeled turnip or celeriac if a fully sweet soup is not what you want at lunch.
- Shredded chicken: Poach two chicken thighs in the broth, shred them, and stir them through the finished soup for a cheaper bowl that still eats like a meal.
- Thinner and brothier: Add another cup of broth after blending and serve it in mugs, which is a good way to use the last of the pot at the end of the week.
Storage & Leftovers
The soup keeps in a sealed container in the refrigerator for 5 days and the duck keeps for 3, so store the two apart rather than together. Let the pot cool for about 30 minutes before the lid goes on. The puree thickens as it chills, which is normal, and a splash of broth loosens it again.
Reheat the soup in a saucepan over medium-low for about 6 minutes, stirring so the bottom does not catch, or in the microwave in 45 second bursts with a stir between them. Warm the duck slices separately in a dry skillet for a minute a side, since reheating them in the soup softens the skin.
The puree freezes for up to 3 months in flat bags or jars with an inch of headroom left at the top. Thaw overnight in the refrigerator and whisk it as it heats, because squash soup often looks grainy at first and comes back together once it is hot. Cook the duck fresh.
Notes & Tips
- Start the duck in a cold pan: A cold skillet and medium heat give the fat time to melt out before the skin sets, which is the whole difference between crisp and chewy.
- Score the fat, not the meat: Cut a crosshatch through the fat cap and stop when you feel the knife reach flesh. Cutting into the meat lets the juices run out during rendering.
- Roast the squash cut side down: Face down on the pan the cut edges caramelize against the metal. Face up they steam, and you lose the browning the soup is built on.
- Keep the leeks pale: Browned leeks turn slightly bitter and that bitterness shows up clearly in a smooth soup. Medium heat, frequent stirring, no color.
- Blend longer than you think: Thirty seconds gives you a soup with grain in it. A full minute and a half is what makes it silky enough that nobody asks what is in it.
- Save the rendered fat: Strain what you poured off into a jar. It keeps in the refrigerator for about a month and makes the next pan of roasted vegetables taste like this soup.
Nutrition & Mindful Eating
- Acorn squash, leeks, and duck each do a different job in the same bowl. The squash gives the soup its body and its sweetness, the leeks give it depth, and the sliced duck across the top is what turns a bowl of blended vegetables into a lunch that carries you through an afternoon.
- Acorn squash roasted until the edges brown tastes far sweeter than it does raw, and that deep orange color is beta-carotene, which the body converts into vitamin A. There is real fiber in the flesh as well, and it is part of why something this smooth still sits steadily through the afternoon.
- Duck breast is dark meat under a thick cap of fat, and rendering it slowly leaves crisp skin above meat that stays rosy and tender. It carries iron in the form the body absorbs most readily along with B12, which is why a few slices change how long the bowl holds you.
- Leeks softened slowly in the rendered fat go silky and sweet rather than sharp, and they bring the kind of fiber the bacteria in your gut feed on. Cooked this gently, they also tend to sit well with people who find raw onion difficult.
- Rosemary goes in early so the fat carries it through the whole pot, and the spoonful of cider vinegar goes in at the very end, off the heat, where it stays sharp. That acid is the reason a sweet puree tastes finished rather than one-note.
- As you eat, let the smooth spoonful and the crisp edge of the duck register as two separate pleasures, and use that contrast as a reason to stay sitting down until the bowl is actually empty.
Frequently Asked Questions
Can I use a different squash?
Yes. Butternut is easier to peel and gives you a smoother, sweeter soup, delicata has thin skin you can leave on, and kabocha makes it noticeably thicker. Keep the roasted flesh at about the same weight and check the roasting time, since thinner-fleshed squash can be done 10 minutes early.
My duck skin came out soft rather than crisp. What happened?
Almost always a hot start. Skin laid into an already hot pan seizes and traps its own fat, so begin in a cold dry skillet over medium and give it the full 10 to 12 minutes. Pat the skin dry before it goes in, and pour off the fat as it collects instead of letting the breast sit and fry in it.
Can I make this ahead for the week?
That is how I use it. Make the soup through the blending step and refrigerate it, then cook the duck the day you want it, or cook it with the soup and keep the slices in their own container. Reheating duck in the soup softens the skin, so warm the slices separately for a minute in a dry pan.
Does this fit an AIP elimination phase?
It does. There are no grains, legumes, dairy, eggs, nuts, seeds, or nightshades in it, and the seasoning is rosemary, garlic, leek, vinegar, and salt. Read the bone broth label, since many cartons carry pepper or paprika, and check that nothing has been added to the duck at the counter.