Crunchy poppy seeds and bright citrus zest combine for tangy, fluffy muffins that are a treat any time of day.
2 cups all-purpose flour
3/4 cup granulated sugar
3 tablespoons poppy seeds
1 tablespoon lemon zest (from 2 medium lemons)
1 tablespoon orange zest (from 1 medium orange)
1 teaspoon baking powder
1/2 teaspoon fine salt
1/2 teaspoon baking soda
1 large egg, at room temperature
1 large egg yolk, at room temperature
8 tablespoons unsalted butter (1 stick), melted
3/4 cup whole milk, at room temperature
2 tablespoons freshly squeezed orange juice
2 tablespoons freshly squeezed lemon juice
1/2 teaspoon vanilla extract
Heat the oven to 350°F and arrange a rack in the middle. Place cupcake liners in a 12-well muffin pan; alternatively, coat the wells with butter. Set the pan aside.
Whisk together the flour, sugar, poppy seeds, zests, baking powder, salt, and baking soda in a large bowl to aerate and break up any lumps; set aside.
Whisk together the egg, yolk, and melted butter in a medium bowl until the eggs are broken up. Add the milk, juices, and vanilla and whisk to combine. Add the wet ingredients to the flour mixture and stir until just evenly combined, about 22 strokes. (Do not overmix; the batter should be thick, but the ingredients should be evenly incorporated.)
Fill the muffin wells about two-thirds of the way and bake until a toothpick inserted into the center of the muffins comes out clean, about 20 to 25 minutes. Set the pan on a wire rack and let the muffins cool in the pan for 5 minutes before serving.