Step 1

Preparation 1. Preheat the oven to 375°F.

Step 2

2. Combine the butter and sugar in the bowl of a stand mixer fitted with the paddle attachment and cream on high until homogenous, about 3 minutes. Add the egg and all of the citrus zests and mix until just combined, about 1 minute.

Step 3

3. Add the flour, salt, baking powder, and baking soda, mixing until just combined, about 30 seconds. Mix in the granola, if using.

Step 4

4. Portion 2 3/4-ounce scoops of dough 2 to 3 inches apart onto a greased or lined baking sheet. Bake the cookies for 9 to 10 minutes, until light golden brown. Cool completely on the pan.

Step 5

Cook's Note:Use a Microplane or the smallest holes of a box grater to zest citrus. Use steady, even force, rotating the fruit as you zest and being careful to remove only the outermost colored layer, not any of the bitter white pith.

Step 6

Reprinted from Milk Bar Life, by Christina Tosi, Copyright © 2015, published by Clarkson Potter/Publishers, an imprint of Penguin Random House LLC.