Introduction

Mango Oatmeal Crumble Bars combine a buttery oat crust with a sweet, tangy mango filling and a crunchy crumble topping. This delightful dessert is perfect for summer gatherings or a sweet everyday treat.

A close-up view of four stacked square peach crumb bars on a white marbled surface, each bar showing three visible layers: a crumbly, light golden brown crust at the bottom, a bright orange peach filling in the middle with juicy fruit chunks, and a crumbly, golden streusel topping with coarse sugar pieces on top, giving a rough and crunchy texture. The bars display moist, soft peach filling peeking through the crumb layers. Photo taken with an iphone --ar 4:5 --v 7

Ingredients

½ cup unsalted butter, melted
1 cup all-purpose flour
¾ cup old-fashioned whole-rolled oats (do not use quick cook or instant)
½ cup granulated sugar
¼ cup light brown sugar, packed
½ teaspoon salt, or to taste
2 cups coarsely chopped fresh ripe mango (fresh Ataúlfo mango recommended; frozen may be substituted if thawed and drained)
⅓ cup granulated sugar
2 tablespoons lemon juice
2 teaspoons corn starch

Instructions

Step 1: Preheat your oven to 350°F (175°C). Line an 8-inch square pan with aluminum foil and spray with cooking spray for easy cleanup; set aside.
Step 2: In a large microwave-safe bowl, melt the butter on high for about 1 minute. Add the flour, oats, granulated sugar, brown sugar, and salt, then stir until combined. The mixture will be dry and sandy with some larger crumble pieces.
Step 3: Set aside 1 heaping cup of this mixture to use later as the crumble topping. Transfer the remaining mixture to your prepared pan and press it down firmly and evenly using a spatula or your fingers to form a smooth crust. Set aside.
Step 4: In the same bowl, combine the chopped mango, ⅓ cup granulated sugar, lemon juice, and corn starch. Toss to mix well. It’s okay if the sugar hasn’t fully dissolved, as it will melt while baking.
Step 5: Evenly spread the mango mixture over the crust in the pan.
Step 6: Sprinkle the reserved crumble topping evenly over the mango layer. For bigger crumble pieces, gently squeeze the topping mixture in your palm before sprinkling.
Step 7: Bake for about 50 minutes, or until the edges are set and the center is just firm. The topping should be pale golden, and the mango filling may bubble at the edges. Depending on mango juiciness, baking may take longer—watch for visual cues rather than relying solely on timing.
Step 8: Remove the pan from the oven and place it on a wire rack to cool completely, at least 1 hour, before slicing. Cooling fully helps the bars hold together and prevents messiness.

Tips & Variations

Use fresh Ataúlfo mangoes for their rich sweetness and creamy texture, but frozen mango can be used if fully thawed and drained to avoid excess moisture.
For added flavor, sprinkle a pinch of cinnamon or ginger into the crumble mixture before baking.
Press the crust firmly and evenly to prevent it from crumbling too much when cutting.
If you prefer a denser filling, reduce the lemon juice slightly to avoid excess liquid.

Storage

Store the bars tightly wrapped at room temperature for up to 1 week or in the refrigerator for up to 10 days. They freeze well too; seal in an airtight container or freezer bag and keep for up to 6 months. To serve, thaw frozen bars in the refrigerator or at room temperature and enjoy.

How to Serve

A stack of four square fruit crumble bars shown close-up on a white marbled texture. Each bar has three visible layers: a bottom layer of light golden brown crumbly crust, a middle layer of bright orange fruit filling with soft chunks, and a top layer of pale crumbly streusel with a rough texture that contrasts with the smooth fruit. The bars are slightly uneven, showing the crumbly texture and juicy filling clearly. Photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I use quick oats instead of old-fashioned rolled oats?

It’s best to use old-fashioned whole-rolled oats because quick or instant oats are finer and can make the mixture too dry and powdery, affecting the texture of the bars.

Can I substitute other fruits for mango in this recipe?

Yes, similar fruits like peaches, nectarines, or berries work well. Adjust the sugar slightly depending on the fruit’s natural sweetness and moisture content.