Notes: You can use your favorite from scratch recipe, like these or these. Or use a mix, I won’t tell!
To make the heart shape I used an approximately 2 3/4-inch heart-shaped cookie cutter and I got 8 heart-shaped brownies out of a 11- x 7- inch pan. You may get more or less depending on the size of your cookie cutter and pan (8- x 8- and 9- x 13- are typical pan sizes for brownies).
For tinting the frosting I prefer gel food coloring, but note that a little goes a long way. Frost the brownies from lightest to darkest, first working with the white frosting then adding drops of color and frosting brownies in progressively darker shades.