How to Make It
Preheat the oven to 375° and butter a 12-cup muffin tin. In a large bowl, whisk together the flours with the baking powder, baking soda and salt. Stir in the millet and quinoa.
In a medium bowl, stir together the brown sugar with the butter, eggs, milk, vanilla and orange zest. Add the wet ingredients to the dry ingredients and stir until combined.
Spoon the batter into the muffin cups and bake until a toothpick inserted into the center of several muffins comes out clean, 18 to 20 minutes. Let cool for 5 minutes. Transfer the muffins to a rack and let cool completely.