Preheat your oven to 350°F (175°C).

Cream together 1 cup of softened unsalted butter and 1 cup of granulated sugar for 3-5 minutes until light and fluffy.

Add 1 large egg and 1 teaspoon of vanilla extract and mix on low speed until mixed.

In a separate bowl, whisk together 2 cups of all-purpose flour, 1 teaspoon of baking powder, and ½ teaspoon of salt, then mix with wet ingredients until just blended.

Prepare the topping by combining 1 cup of rolled oats, ½ cup of brown sugar, and remaining flour mixture.

Press half of the dough mixture into a greased 9x13 inch baking dish.

Spread 1 cup of raspberry jam evenly over the cookie base.

Sprinkle the remaining crumble topping over the jam and press down gently.

Bake in the preheated oven for 25-30 minutes until golden brown.

Allow to cool in the pan for 10-15 minutes before transferring to a wire rack.