- 5/8 cup milk, at room temperature
- 3 3/4 teaspoons lemon juice
- 1/4 cup vegetable oil
- 2 egg whites, room temperature
- 2 lemons, zested
- 1 1/2 teaspoons vanilla extract
- 1 1/8 cups gluten-free flour (such as Jeanne's Gluten-Free All-Purpose Flour Mix; recipe in footnotes)
- 3/4 cup white sugar
- 2 teaspoons double-acting baking powder
- 1/4 teaspoon salt
- Preheat oven to 350 degrees F (175 degrees C). Line 12 muffin cups with paper liners.
- Whisk milk and lemon juice together in a bowl. Beat vegetable oil, egg whites, lemon zest, and vanilla extract into milk mixture.
- Combine gluten-free baking flour, sugar, baking powder, and salt together in a large bowl. Add milk mixture to flour mixture; beat on medium speed with an electric mixer until batter is well mixed, about 2 minutes. Spoon batter into lined cups to about 3/4-full.
- Bake in the preheated oven until tops are a light golden brown and a toothpick inserted in the center of the cupcake comes out clean, 18 to 20 minutes. Cool cupcakes in the muffin tin for 10 minutes before transferring to a wire rack to cool completely.