Preheat oven to 350°F. Line a 9-inch square baking pan with parchment paper, leaving a 2-inch overhang on all sides. Stir together flour, cocoa, salt, and baking powder in a small bowl; set aside.

Place eggs, granulated sugar, brown sugar, and vanilla in a large bowl. Beat with an electric mixer on high speed until pale and thick, about 1 minute.

Microwave butter in a small microwavable bowl on HIGH until melted, about 30 seconds. Add 1 cup of the chocolate chips to melted butter; stir until chocolate is melted. Add to egg mixture; stir until combined. Add flour mixture; stir until combined. Spoon mixture into prepared baking pan; spread into an even layer (mixture will be thick). Bake in preheated oven until a wooden pick inserted in center of brownies comes out with a few moist crumbs and tops are set, about 25 minutes. Let cool on a wire rack 1 hour.

Heat cream in a small saucepan over medium, undisturbed, until bubbles appear around edges of pan. Remove from heat. Add remaining 1 1/2 cups chocolate chips; whisk until chocolate is melted. Arrange strawberries, cut sides down, on top of cooled brownies in pan. Pour cream-chocolate mixture over strawberries. Place brownies in freezer; let chill until cream-chocolate layer is firm, 2 to 3 hours.

Using parchment overhang as handles, lift and remove brownies from pan. Carefully run hot water over a knife; wipe knife dry. While knife is still hot, cut brownies evenly into 12 squares. (Reheat knife with hot water as needed.) Let brownies come to room temperature, about 30 minutes. Serve.