01 -
Heat your oven to 350 degrees. Lightly grease a 9x13 inch baking dish or spray it with nonstick cooking spray, then line it with parchment paper so you can lift the bars out easily later. Set it aside.
02 -
In a large mixing bowl or stand mixer, cream together the softened butter and brown sugar for 2 to 3 minutes until the mixture is light and creamy. Mix in the flour and salt until just combined - the dough should be crumbly but hold together when you press it.
03 -
Set aside about 2/3 cup of the dough mixture for the crumble topping. Press the rest of the dough evenly into the bottom of your prepared baking dish to form a thin crust layer.
04 -
Bake the crust for 10 minutes or until it just starts to turn golden brown around the edges.
05 -
While the crust is baking, stir the chopped pecans or walnuts into the reserved dough mixture. This will be your crumb topping.
06 -
In a microwave-safe dish, combine the sweetened condensed milk and bittersweet chocolate chips. Heat on medium power in 30-second bursts, stirring well between each one, until the chocolate is completely melted and smooth.
07 -
Pour the melted chocolate mixture evenly over the hot baked crust. Use an offset spatula to spread it out smoothly.
08 -
Sprinkle the crumb topping with nuts evenly over the chocolate layer. Drop small spoonfuls of raspberry preserves all over the crumb topping - if the preserves are too thick to drop easily, stir in a tablespoon of water to thin them out. Finally, sprinkle the semi-sweet chocolate chips over everything.
09 -
Bake for 25 minutes or until the topping is set and golden brown.
10 -
Take the pan out of the oven and let the bars cool completely before cutting into 24 pieces. These are really rich, so cutting them into smaller bars is perfect!