Preheat oven to 350°. Melt butter, then combine with brown sugar, vanilla, and eggs using hand mixer on low speed.
Mix together flour, salt and baking powder. Slowly stir dry ingredients into wet mixture.
Grease loaf pan. Pour batter into greased pan, smooth with spatula.
Bake 40-50 minutes until edges are golden brown and middle is solidly cooked through (an inserted toothpick should come out clean). If top gets too golden before middle is cooked, cover with foil until done. Allow to cool in pan before removing. Once cool, gently remove brownie loaf from pan. Slice loaf in half lengthwise, horizontally to form two cake layers.
*Pro Tip: remove rounded top of loaf to form more perfect rectangles, if needed.
Remove ice cream from freezer and allow to slightly soften (just a few minutes).
Chocolate shell: Melt chocolate chips and coconut oil together in microwave, or over stove using double boiler. Stir until well combined and silky smooth. Allow to cool. Stir again before using.
Take cake out of freezer just before serving. Remove cake from pan by flipping it upside down. Peel off plastic wrap. Pour chocolate shell over top of cake, letting it naturally drip down edges of cake.