Adjust oven rack to the middle position, and preheat the oven to 350℉.
Line an- 8x8-inch baking pan with parchment paper, folding it so it covers the bottom of the pan and hangs over two opposite edges.
Place the almond flour, white sugar, cornstarch, and salt in the food processor. Cut 6 tablespoons of the cold butter into ½-inch pieces and sprinkle over the dry ingredients. Pulse 25 times or until the dough resembles wet sand.
Pour the almond flour-butter mixture into the prepared pan, and using fingers or a spatula, press it in firmly into an even layer.
Bake for 15-20 minutes, or until edges begin to brown. Remove the crust from the oven and let it rest for at least 5 minutes. Make sure it's firm and set.
While the crust is baking. combine the preserves, lemon juice and fresh raspberries in a small bowl. Mash gently with a fork to break up some of the berries, but leave some whole. Set this aside.
Combine the brown sugar, pecans, oats, and remaining 4 tablespoons of butter in the food processor. Pulse about 30 times or until the mixture forms clumps.
When the crust has cooled and is set, carefully spoon the raspberry filling onto the crust. Use a spatula to gently spread the filling over the warm crust. Sprinkle the oat mixture evenly over the top and gently pat it but don't press it in.
Return pan to the oven and bake for another 22 to 25 minutes, until filling is bubbling and topping is a deep brown color.
Cool to room temperature on a wire rack. Remove from the baking pan by lifting overhanging foil. Using a chef's knife, cut into 12 squares.