Start to finish: 10 minutes
Makes: 10 cups (enough for 30, 4-inch waffles)
1½ cups buttermilk powder
6 cups flour
1 cup powdered sugar
2 cups cornstarch
6 tablespoons baking powder
2 teaspoons salt
Sift all ingredients into a large bowl and whisk to combine. Use a funnel to pour into an airtight container and store until ready to use.
Bring a waffle iron to medium-high heat.
Combine 2⅓ cups waffle mix with 1½ cups water, 7 tablespoons melted butter and 2 eggs. Whisk until just combined; a few lumps are OK.
Spritz waffle iron with cooking spray then ladle in ¼–½ cup batter, depending on the size of the iron.
Let cook until crispy and browned on the outside — about 4–5 minutes depending on the iron.
Remove with a fork and serve immediately, or place on a baking sheet topped with a cooling rack and keep warm in a 250 F oven.