Preheat oven to 350°F. Grease a 9" x 13" baking pan. Line with parchment and grease the parchment, too. This extra step will help when it comes to cutting and removing the bars.
Use a mixer to whip the butter until creamy. Mix in flour and brown sugar until combined and crumbly. Press 1 3/4 cups of crumb mixture into prepared baking pan. Set aside the rest for topping. Bake for 10-12 minutes, until lightly golden.

Meanwhile, pour can of sweetened condensed milk into a microwave-safe cooking dish. Add 1 cup semi-sweet chocolate chips and heat on high for 30 seconds. Stir and heat for another 20-30 seconds; stir again. Stir (and heat again if necessary) until chips are completely melted and mixture is smooth.

When crust is done, remove from oven and pour chocolate mixture over crust. Scatter remaining crumbs over chocolate layer, top with raspberries and sprinkle with mini chocolate chips.

Bake for 25-30 minutes. Let cool completely before cutting into bars. Store in fridge or freezer.