Directions

• Step 1: Preheat your oven to 350°F (175°C). Line a 9x13-inch baking pan with parchment paper, allowing some overhang for easy removal later.
• Step 2: In a large mixing bowl, combine the old-fashioned oats, all-purpose flour, brown sugar, baking powder, and cinnamon. Mix well. Next, add the cubed cold salted butter. Using a pastry cutter or your fingers, work the butter into the dry ingredients until the mixture resembles coarse crumbs.
• Step 3: Set aside approximately 1 ½ cups of the crumble mixture for the topping. Press the remaining crumble mixture firmly into the bottom of the prepared baking pan to form the base layer.
• Step 4: In another bowl, combine the fresh raspberries, brown sugar (to taste), 2 tablespoons of flour, vanilla extract, and lemon zest. Gently fold to combine, taking care not to crush the berries too much.
• Step 5: Spread the raspberry mixture evenly over the pressed crumble base. Then, drop spoonfuls of raspberry jam over the filling to add extra flavor.
• Step 6: Sprinkle the reserved crumble mixture over the raspberry layer, ensuring it covers the filling evenly.
• Step 7: Place the baking pan in the preheated oven and bake for 35-40 minutes, or until the top is golden and the filling is bubbly.
• Step 8: Once baked, remove the pan from the oven and allow it to cool in the pan for at least 20 minutes. Then, use the parchment paper overhang to lift the bars out onto a cutting board. Allow to cool completely before slicing into squares.