Preheat the oven to 350 degrees.
In an electric mixer, beat butter and sugar until combined.
Add in the vanilla extract.
Add in the flour, salt, and baking powder and blend on low until incorporated.
Prepare a 9x9 baking dish by buttering the bottom and adding parchment paper to it. Let the sides overhang so the bars can easily be removed. Note - You can use a 13 x 9 rectangular pan as well. The crust will be a little thinner.
Divide the dough in half and place one half in the refrigerator and evenly press the other half into the bottom of the baking dish.
Refrigerate the pressed dough in the baking dish for 30 minutes.
Bake the dough for 15 minutes, then remove.
Spread 12 ounces raspberry preserves (or any preserves you want!) over the top and then crumble the other half of the dough over the preserves.
Bake for another 25 minutes. Note, that baking times vary. If you need an extra 5-10 minutes then that is okay! You need to be able to check and tell when your crumble bars are finished. They will have a very slight, golden brown color to them.
Remove from the oven and let them cool, then dust powdered sugar over the top.
Cut them into squares and enjoy!