Slow Cooker Steel-Cut Oats with Apple and Cinnamon
Steel-cut oats cooked overnight with milk, diced apple and cinnamon so breakfast is waiting in the morning.
Why You'll Love This Recipe
Steel-cut oats are the one breakfast grain that genuinely rewards a slow cooker. They need something like forty minutes of stirring on a stove to get where they are going, which is why most people buy the rolled kind and never think about it again. Seven hours under a lid gets them to the same place overnight and asks nothing of anybody, and the texture at the end is the reason to bother: whole, chewy grains in something creamy, rather than the soft paste rolled oats give you.
The apple goes in raw and in small cubes rather than grated. Over a long cook the pieces soften completely but hold their edges, so you get pockets of sweetness scattered through the oats rather than one uniformly sweet pot. Grated apple would dissolve entirely and take that contrast with it. The apple is also doing most of the sweetening here, which is why two tablespoons of maple syrup across six servings is enough to notice and not enough to taste like syrup.
The part nobody tells you is that oats scorch at the edge of a crock overnight, along the line where the liquid meets the wall and dries out first. Buttering or oiling the insert before anything goes in solves it. If your slow cooker runs hot, there is a second trick worth knowing: set a heatproof bowl of the oats inside the crock with an inch of water around it, which turns the whole thing into a water bath and takes the problem off the table for good.
Ingredients
- 1 1/2 cups dry steel-cut oats
- 5 cups 2% milk
- 2 apples, cored and cut into small cubes
- 1 1/2 tsp ground cinnamon
- 3 tbsp ground flaxseed
- 2 tbsp maple syrup
- 1/4 tsp salt
- 1/3 cup chopped walnuts, for serving
Instructions
- Grease the crock, sides included: Rub the inside of a 6-quart slow cooker with a little butter or oil, going right up the sides. Oats stick and scorch along the waterline over a long cook, because that is where the liquid dries out first, and this one step is what prevents it.
- Add the oats and the milk: Put the steel-cut oats into the crock and pour the milk over them, then stir once so that no dry oats are left sitting against the sides above the liquid. Any that are will toast rather than soften, and you will find them in the morning as hard specks in an otherwise creamy pot.
- Stir the apple and spices through: Add the diced apple, cinnamon, ground flaxseed, maple syrup, and salt, then stir until the cinnamon is evenly distributed rather than floating in patches on the surface. Cinnamon that starts in a raft on top mostly stays there, which gives you one strongly spiced spoonful and a pot of plain oats underneath it.
- Cook on low for 7 hours, lid on: Cover and cook on low for 7 hours. Do not lift the lid partway through, since a slow cooker loses a good deal of heat every time it is opened and takes twenty minutes or more to recover, and these oats have no spare time in the schedule.
- Stir it back together in the morning: In the morning the oats will look separated with a layer of liquid sitting on top, which is normal and not a failure. Stir firmly for a few seconds and they come back together into something thick and creamy as the starch redistributes through the pot.
- Serve, and loosen any bowl that needs it: Spoon the oats into bowls and top them with the chopped walnuts. Add a splash of milk to any bowl that has gone thicker than you want, because the oats keep tightening as they sit and a portion taken out on the third day will be noticeably stiffer than the first.
Variations
- Instant Pot: Cook on high pressure for 4 minutes with a natural release of 15, using 1 cup less milk since nothing evaporates.
- Pumpkin spice: Stir in a cup of pumpkin puree with a half teaspoon each of ginger and allspice. It goes deeper and more autumnal and needs no extra sweetener.
- Banana walnut: Skip the apple and mash two ripe bananas into the milk before cooking. The bananas sweeten it enough that you can leave the maple out entirely.
- Berry and almond: Leave the apple out and stir a cup and a half of frozen berries into the hot oats at the end, then top with sliced almonds instead of walnuts.
- Higher protein: Stir a scoop of unflavored or vanilla protein powder into each bowl after cooking rather than into the crock, where the heat would make it grainy.
Storage & Leftovers
Cooled leftovers keep in the refrigerator for 5 days and this is exactly what I make them for. Portion them into individual jars while still warm so you are not fighting a solid block later in the week.
Reheat a portion with a splash of milk or water, either in a covered pan over low heat or in the microwave in short bursts with a stir in between. Cold steel-cut oats set firm, and the liquid is what brings them back.
They freeze for up to 3 months. Freeze in single portions, thaw overnight in the refrigerator and reheat with extra liquid. Add the walnuts fresh rather than freezing them in, since they soften and lose their snap.
Notes & Tips
- Grease the crock first: Thirty seconds with butter or oil on the sides is the difference between creamy oats and a scorched ring you have to scrub off.
- Steel-cut only: This method depends on a grain that can take seven hours. Rolled and instant oats both break down into paste long before morning.
- Keep the lid on: Every peek costs a slow cooker real heat and adds twenty minutes. There is nothing to check on here, so leave it alone.
- Stir hard in the morning: Separated oats with liquid pooled on top look wrong and are not. A firm stir brings them back to creamy in a few seconds.
- Dice the apple small: Half-inch cubes soften without dissolving. Grated apple disappears and large chunks stay watery in the middle.
- Portion while warm: Warm oats spoon into jars easily. Cold ones set into a single mass you have to chip apart, which is how a good batch stops getting eaten.
Nutrition & Mindful Eating
- Steel-cut oats are the whole groat cut into pieces rather than steamed and flattened, which is why they hold their shape overnight and why they digest more slowly than a rolled oat does.
- The soluble fiber in oats is beta-glucan, and it is the reason a bowl of oatmeal sits with you longer than most breakfasts of the same size.
- Ground flaxseed adds omega-3 fats and more fiber, and it has to be ground rather than whole, since whole flaxseeds pass through mostly intact and give you very little.
- Five cups of milk across six servings is doing quiet work here, lifting the protein of this bowl well above what plain oats give you and supplying most of its calcium.
- Two tablespoons of maple syrup across six servings works out to about a teaspoon each. The apple is doing most of the sweetening, which is what keeps the added sugar low in a breakfast that usually has a lot of it.
- As you eat, notice how much longer a spoonful of steel-cut oats takes to break down than a soft cereal does, and let that slow the whole bowl.
Frequently Asked Questions
Can I use rolled oats instead?
Not for this method. Rolled oats turn to glue over seven hours. If rolled oats are what you have, cook them for 2 hours on low or make them on the stove in ten minutes instead.
Why did mine burn at the edges?
Almost every slow cooker has a hot spot and oats are thick enough to sit against it. Grease the crock, or set a heatproof bowl of oats inside with an inch of water around it so nothing touches the hot surface directly.
Can I make it dairy free?
Yes. Unsweetened almond, soy or oat milk all work in the same quantity. The nutrition on this page is calculated with 2% milk, so a plant milk version will read lower in protein unless you use soy.
Can I halve the recipe?
You can, but use a smaller slow cooker if you have one. A half batch spread thin across a 6-quart crock has too much surface area and cooks dry at the edges before the center is done.