• Preheat the oven to 35°0F and line 2 baking sheets with parchment paper.

Make the Cookie Dough

• Brown the butter on medium-low heat until brown flecks appear.  Remove from heat and allow the browned butter to cool for 5 minutes.
• In a small bowl, whisk together the dry ingredients - flour, beetroot powder, salt, and baking soda.  Set aside.
• In a large mixing bowl or bowl of a stand mixer, whisk/mix browned butter and 2 cup of sugar together for 2 minutes at low speed.  Add the egg yolks, sourdough starter, and vanilla and mix well.
• Add the dry ingredients to the wet ingredients and mix.  Stir in the white chocolate chips.

Bake the Cookies

• Spoon the dough onto a prepared baking sheet and use the back of a spoon to flatten it to 1/4” thick circles, or roll the dough into a sheet and use a heart-shaped cookie cutter to cut the cookies.
• Bake at 350°F in the preheated oven for 10 minutes or until the edges are just golden brown and the center of each cookie is still a bit gooey.
• Set the cookies on a cooling rack to cool before serving.