I start by melting the butter and unsweetened chocolate together. This gives the brownies a deep, fudgy texture. Meanwhile, I measure the sugar, flour, and other dry ingredients.
I whisk the eggs and vanilla into the chocolate mixture, then fold in the dry ingredients slowly. Adding chocolate chips and M&Ms at this stage makes sure every bite has little surprises.
Pour the batter into the lined baking pan and press a few M&Ms on top. Bake at 350°F for about 25 minutes, or until the edges look set but the center is still soft.
Once cooled completely, I lift the brownies out using the parchment overhang. Then, I press the cookie cutter gently into the brownies for perfect heart shapes.