Gruyere adds a rich nuttiness to these savory muffins.
Preheat oven to 400 degrees. Line a standard 12-cup muffin tin with baking cups, or lightly brush with butter. In a medium bowl, whisk together flour, wheat germ, baking powder, sugar, salt, and pepper. In another bowl, whisk together butter, milk and eggs. Stir wet ingredients into dry until just combined. Fold in zucchini and 2/3 cup cheese.
Divide batter evenly among muffin cups and sprinkle with remaining 1/3 cup cheese. Bake until golden and tops spring back when lightly touched, about 18 minutes. Let cool 5 minutes in tin, then transfer to a wire rack and let cool completely.
To quickly bring cold eggs to room temperature, cover them in a bowl full of hot water while you measure the other ingredients.