Adjust oven rack to middle position and heat oven to 325 degrees. Grease two 9-inch round cake pans, line with parchment paper, grease parchment, and flour pans. Sift flour and cocoa into large bowl. Whisk in sugar, baking soda, baking powder, spice mix and salt. Whisk yogurt, beer, oil, eggs, and vanilla together in second bowl. Whisk yogurt mixture into flour mixture until smooth batter forms. Divide batter evenly between prepared pans and smooth tops with rubber spatula.

Bake until toothpick inserted in center comes out clean, 22 to 28 minutes, switching and rotating pans halfway through baking. Let cakes cool in pans on wire rack for 15 minutes. Remove cakes from pans, discarding parchment, and let cool completely on rack, at least 2 hours.

Prepare Easy Frosting. Add food coloring to preference.