Preheat the oven to 350 °. Line 2 muffin pans with cupcake papers.
Combine the cake mix, yogurt, water, oil, eggs, and lemon zest in a large mixing bowl. Blend 2 minutes with an electric mixer until smooth.
Spoon the batter into the prepared cupcake papers. Bake according to package directions. Cool completely on a rack.
Frost cooled cupcakes with lemon buttercream, if desired.
Notes
Store cooled cupcakes, unfrosted, covered at room temperature for up to 2 days. Frosted cupcakes should be stored in the fridge - bring back to room temperature before serving