Cinnamon Brown Sugar Baked Oatmeal
A cozy, sliceable baked oatmeal with a custardy middle and golden, lightly crisp edges, flavored with cinnamon, brown sugar and vanilla. Mix it in one bowl, bake, and serve warm with milk or yogurt.
- Prep
- 12 min
- Cook
- 35 min
- Wait
- 10 min
- Total
- 57 min
- Makes
- 1 8-inch (20 cm) square pan (6 squares)
Steps
Before you start
- Position an oven rack in the center and preheat to 350°F (175°C).
- Use old-fashioned rolled oats, not instant or steel-cut; they give the right texture and absorb the right amount of milk.
- Take the milk and eggs out of the fridge 15 minutes ahead so the melted butter doesn't clump when mixed in.
- Plan for 10 minutes of resting after baking so the oatmeal sets and cuts into clean squares.
Preheat and prep panOven 350°F / 175°C
- Position a rack in the center of the oven and preheat to 350°F (175°C).
- Rub the inside of an 8×8-inch (20 cm) baking dish with a little butter, covering the bottom and sides.
- Melt the 3 tablespoons of butter in a small saucepan or microwave and set aside to cool slightly.
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Ready when: Dish is evenly coated with a thin film of butter.
Mix dry ingredients
- In a large bowl, stir together the oats, brown sugar, baking powder, cinnamon and salt.
- Break up any lumps of brown sugar with your fingers or the back of a spoon.
- If using walnuts, stir in 6 tablespoons (about 45 g) now and save the rest for the top.
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Ready when: No visible clumps of sugar; cinnamon is evenly distributed.
Whisk wet ingredients
- In a medium bowl, whisk the milk, eggs and vanilla until the eggs are fully broken up.
- Slowly whisk in the cooled melted butter in a steady stream.
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Ready when: Mixture is smooth with no streaks of egg white or pools of butter.
Tip: If the butter is hot it can scramble the eggs; let it cool until just warm to the touch first.
Combine and fold
- Pour the wet mixture over the oat mixture and stir with a spatula until all the oats are moistened.
- Gently fold in 3/4 cup (110 g) of the blueberries if using, keeping the rest for the top.
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Ready when: Batter looks loose and wet, with milk visible around the oats.
Tip: Don't worry that it looks thin; the oats absorb the liquid as it bakes.
Fill the dish
- Scrape the batter into the prepared dish and spread it level.
- Scatter the remaining blueberries and walnuts over the top and press them lightly into the surface so they stay put.
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Ready when: Surface is level and the batter just reaches about 1 inch (2.5 cm) up the sides.
BakeOven 350°F / 175°C
- Bake on the center rack at 350°F (175°C) for 35 to 40 minutes.
- It is done when the top is golden brown, the edges pull slightly away from the pan, and the center feels set and springs back when lightly pressed.
- A thermometer in the center should read 160°F (71°C).
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Ready when: Golden top, edges pulling from the pan, center springy with no liquid jiggle.
Tip: If the top browns too fast before the center sets, tent loosely with foil for the last 10 minutes.
Rest and serve
- Let the baked oatmeal rest in the pan on a wire rack for 10 minutes so it firms up.
- Cut into 6 squares and serve warm with a splash of cold milk, yogurt or a drizzle of maple syrup.
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Ready when: Squares hold their shape when lifted with a spatula.
Tip: Cutting right away gives soft, messy squares; the rest time matters.
Good to know
Tips
- Use rolled oats; quick oats turn mushy and steel-cut oats stay hard.
- Frozen blueberries can bleed color; fold them in gently and don't thaw them.
- For crisper edges, bake in a metal pan; a glass dish gives a softer result and may need a few extra minutes.
- Doubling the recipe works in a 9×13-inch (23×33 cm) pan; bake 40 to 45 minutes.
Make ahead
"Mix the dry ingredients and store airtight up to 1 week. Whisk the wet ingredients and refrigerate separately overnight, then combine and bake the next morning (add 3 to 5 minutes if the batter is cold)."
Storage & reheating
"Room temperature: up to 2 hours after baking. Fridge: cover tightly and store up to 5 days. Freezer: wrap squares individually and freeze up to 3 months; thaw overnight in the fridge. Reheat a square in the microwave for 45 to 60 seconds, or in a 325°F (165°C) oven for 10 minutes, with a splash of milk."
Substitutions
- whole milk → unsweetened oat or almond milk. Works 1:1; the result is slightly less rich.
- unsalted butter → coconut oil or neutral oil. Use the same amount, melted.
- light or dark brown sugar → maple syrup. Use 1/4 cup (60 ml) and reduce the milk to 1 1/3 cups (320 ml).
- fresh or frozen blueberries → diced apple or sliced banana. Use 1 cup (about 150 g); apple may need 5 extra minutes of baking.
