Preheat and Prep

Preheat your oven to 350°F (175°C).

Line a 9×13-inch baking dish with parchment paper or lightly coat it with non-stick spray.

Make the Oat Crumble

In a large mixing bowl, beat together the softened butter, granulated sugar, and brown sugar until light and fluffy.

Stir in the baking soda, salt, flour, and quick oats. Mix until fully combined and crumbly.

Press half of this oat mixture evenly into the bottom of the prepared pan—no need to measure precisely.

Parbake the Base

Place the pan in the oven and bake for 13 minutes, just until lightly set.

Remove from oven and set aside.

Prepare the Cream Cheese Filling

In a medium bowl, stir the cream cheese until smooth and lump-free.

Slowly whisk in the sweetened condensed milk until fully incorporated.

Add the vanilla extract and egg yolk, stirring until smooth.

Assemble the Layers

Pour the cream cheese mixture over the partially baked crust and gently spread it into an even layer.

Distribute the blueberries (or raspberries) evenly over the cream cheese filling.

Sprinkle the remaining oat crumble over the berries, pressing lightly to help it adhere.

Final Bake

Return the pan to the oven and bake for an additional 20–25 minutes, or until the edges are golden and the center is just set.

Allow the bars to cool completely in the pan, then refrigerate for at least 2 hours before cutting into squares.