Begin by quartering your boiled and peeled beets, then place them in a food processor. Blend until smooth, achieving a velvety beet puree that should measure about 1 cup.

Preheat your oven to 350°F (180°C). Line a 9x9-inch brownie pan with parchment paper or grease it thoroughly.

In a medium saucepan, combine the chopped dark chocolate and unsalted butter. Melt over low heat, stirring continuously for about 5 minutes until smooth.

In a large mixing bowl, whisk together the white whole wheat flour, baking powder, and salt until well combined.

Using a stand mixer, beat the eggs on medium speed for about 30 seconds. Add in the vanilla extract and golden brown sugar, mixing until lightened in color. Gradually blend in the beet puree and cooled chocolate mixture.

Gently add the flour mixture to the wet ingredients in the stand mixer, mixing on low speed until just combined. Avoid overmixing and fold in optional ingredients if desired.

Pour the batter into the prepared pan, smoothing the top evenly. Bake for 25-30 minutes, checking for moist crumbs with a toothpick.

Once baked, cool the brownies in the pan for about 5 minutes before transferring them to a wire rack to cool completely.