Blueberry Baked Oatmeal Squares

Created on February 7th, 2026 at 08:46 am

Blueberry baked oatmeal squares are built for mornings when you want something filling without cooking a full breakfast every day. Instead of a bowl of oatmeal that must be made fresh, this version bakes in one pan and cools into sliceable squares. That means you can portion it once, store it, and reheat as needed.

Fresh blueberries are the dominant ingredient in the flavor and texture. As they bake, they soften and release a little juice, which keeps the oatmeal tender. Rolled oats give structure, eggs help the squares set, and baking powder adds a lighter feel so the finished bars are not dense.

These squares work for weekday meal prep, family breakfasts, or a simple weekend bake that gives you several servings with minimal effort.

Time Breakdown

• Prep time: 15 minutes
• Bake time: 35 to 40 minutes
• Cooling time: 20 minutes
• Total time: about 1 hour 15 minutes

Ingredients

Main ingredients

• 2 cups old-fashioned rolled oats
• 1 1/2 cups fresh blueberries

Wet ingredients

• 1 3/4 cups milk (any dairy milk works)
• 2 large eggs
• 1/3 cup maple syrup
• 3 tablespoons unsalted butter, melted and slightly cooled
• 2 teaspoons vanilla extract

Dry seasonings

• 1 1/2 teaspoons baking powder
• 1 teaspoon ground cinnamon
• 1/2 teaspoon fine salt

Optional for serving

• Extra blueberries
• Yogurt
• Nut butter
• A small drizzle of maple syrup

Kitchen Tools

• 8×8-inch baking dish (glass or ceramic works well)
• Mixing bowl
• Whisk
• Rubber spatula
• Measuring cups and spoons
• Cooling rack (helpful but not required)

Step by Step Instructions

Step 1: Heat the oven and prep the pan

Preheat the oven to 375°F. Set a rack in the middle of the oven so the center of the oatmeal bakes evenly. Lightly grease an 8×8-inch baking dish with butter or neutral oil. If you prefer the cleanest slices, line the dish with parchment paper, leaving a bit of overhang on two sides so you can lift the baked oatmeal out after cooling.

Step 2: Mix the wet ingredients first

In a large mixing bowl, whisk the milk and eggs until the eggs are fully broken up and the mixture looks uniform. Add the maple syrup, melted butter, and vanilla extract, then whisk again until the mixture is smooth. If your butter is very hot, let it cool for a few minutes before adding so it does not warm the eggs too quickly.

Step 3: Add the dry ingredients and fully combine

Sprinkle the baking powder, cinnamon, and salt over the wet mixture. Whisk for 15 to 20 seconds so the baking powder and spices disperse without clumps. This helps the oatmeal rise evenly and prevents pockets of cinnamon.

Step 4: Stir in the oats and rest briefly

Add the rolled oats and stir with a spatula until every oat is coated and there are no dry patches. Let the mixture rest for 5 minutes. This short rest gives the oats time to start absorbing liquid, which improves the final texture and helps the baked oatmeal slice cleanly.

Step 5: Fold in the blueberries gently

Add the fresh blueberries and fold them in with slow, gentle turns. Try not to crush many berries. Whole berries give you visible bursts of fruit and keep the mixture from turning purple. If some berries break, that is fine, but aim to keep most intact.

Step 6: Fill the pan and level the surface

Pour the oat mixture into the prepared baking dish. Use the spatula to spread it into an even layer, then lightly tap the pan on the counter once or twice to settle the mixture. If blueberries are clustered, nudge a few toward empty areas so every slice gets fruit.

Step 7: Bake until set and lightly golden

Bake for 35 to 40 minutes. The edges should look lightly golden, and the center should feel set when you gently press the top with a fingertip. Another clue: the surface will look less glossy, and the middle will not jiggle like liquid when you nudge the pan.

If you use a deeper pan or your blueberries are extra juicy, you may need a few more minutes. Avoid overbaking, which can dry the edges.

Step 8: Cool for clean slices

Place the pan on a cooling rack and let it cool for at least 20 minutes before slicing. Cooling is what turns baked oatmeal into squares. If you slice too soon, the pieces can crumble because the steam inside has not settled.

For very neat slices, cool fully, then refrigerate for 30 minutes and slice with a sharp knife wiped clean between cuts.

Step 9: Slice and serve

Slice into 9 squares for larger portions or 12 squares for smaller portions. Serve warm, room temperature, or chilled. If serving warm, a spoonful of yogurt or nut butter on top pairs well with the blueberries.

Pro Tips

• Use rolled oats: Quick oats make a softer, less structured bake. Rolled oats give the best sliceable texture.
• Do not skip cooling: Cooling is part of the “set time.” It is the difference between spoonable oatmeal and squares.
• Even blueberry spread: Fold gently, then redistribute berries on top before baking if one side looks sparse.
• Reheating tip: Add a tiny splash of milk before reheating to keep the texture moist.

Serving Suggestions

• Serve with plain Greek yogurt and a few fresh blueberries on top.
• Spread a thin layer of peanut butter or almond butter on a warm square.
• Pack a square in a lunchbox with a small container of yogurt for dipping.
• For a slightly sweeter plate, drizzle a small amount of maple syrup right before serving.

Ingredient Swaps That Still Bake Well

If you want to adjust this recipe without changing the basic method, keep the oat-to-liquid balance similar. You can replace up to 1/2 cup of the milk with plain yogurt for a slightly tangier flavor and a softer bite. You can also add 1/4 cup chopped walnuts or pecans for texture, or stir in 2 tablespoons ground flaxseed for a thicker batter. If you add dry extras, add an extra 2 to 3 tablespoons milk so the squares do not bake up dry.

Nutrition Table

Approximate nutrition per serving (1 of 9 squares):

Nutrient	Amount
Calories	230 kcal
Carbohydrates	34 g
Protein	7 g
Fat	8 g
Saturated Fat	4 g
Fiber	4 g
Sugar	11 g
Sodium	210 mg
Potassium	220 mg
Calcium	120 mg
Iron	1.8 mg
Vitamin A	220 IU
Vitamin C	6 mg

Disclaimer: Nutrition facts are estimated using online tools and may vary based on your ingredients and preparation. Please consult a nutritionist for precise dietary advice.

FAQ: Blueberry Baked Oatmeal Squares

Can I use frozen blueberries instead of fresh?

Yes. Use frozen blueberries straight from the freezer to limit extra liquid. If your frozen berries look very icy, toss them with 1 teaspoon cornstarch before folding in to help control moisture.

How do I store baked oatmeal squares?

Cool completely, then store in an airtight container in the refrigerator. They keep well for about 3 to 4 days.

Can I freeze baked oatmeal squares?

Yes. Cool completely, slice, then freeze the squares in a single layer before transferring to a freezer bag or container. They keep well for up to about 3 months.

Can I make this the night before?

Yes. Mix the batter, cover, and refrigerate overnight, then bake in the morning. If it looks thicker after chilling, stir in 1 to 2 tablespoons milk before baking.

Can I make baked oatmeal without eggs?

Yes. A common approach is to replace eggs with a flax egg, or use mashed banana or applesauce in some baked oatmeal recipes. Note that egg-free versions may be slightly softer and less sliceable