Place butter in a large bowl and heat in your microwave or on a double broiler until melted. You can also melt the butter in a pot on your stove top. Add your brown sugar and granulated sugar to the butter while it's still hot. Whisk to incorporate. - ½ cup (1 stick / 115g) unsalted butter, ½ cup (100g) dark brown sugar, ½ cup (100g) granulated sugar

Add your room temperature eggs and vanilla extract to the butter / sugar mix. Whisk until everything is incorporated. - 2 large eggs, 1 teaspoon vanilla extract

Add flour, cocoa powder, salt, and baking soda to the wet ingredients along with any add-ins you'd like (I added chocolate chips). Fold the ingredients together until everything is fully incorporated and you no longer see any dry ingredients. - ½ cup (60g) all-purpose flour, ½ cup (40g) unsweetened cocoa powder, ¼ teaspoon salt, ¼ teaspoon baking soda, ½ cup (4 ounces) semisweet chocolate chips

Pour your batter into your prepared baking dish. Place your baking dish into the center of a preheated 350°F oven. Bake for 25 to 30 minutes, or until a skewer inserted into the center comes out clean of batter, but with a few wet crumbs.

Allow the brownie to cool in the baking dish for 10 to 15 minutes. Transfer to a wire rack to finish cooling. Slice your brownies. Serve plain or top with some ice cream, melted chocolate, chopped nuts, or whatever else you like!