1. Preheat oven to 400°. Cover 2 metal baking pans with parchment paper.
2. Weigh or lightly spoon flour into dry measuring cups; level with a knife. Place flour in a large bowl.
3. Combine milk and oil in a small saucepan over medium heat; bring to a boil. Slowly pour milk mixture into flour, stirring until blended. Let cool 5 minutes. Add eggs and cheeses, stirring until blended. Place dough in refrigerator, and chill 20 minutes.
4. Turn dough out onto a well-floured surface. With floured hands, shape dough into 15 balls, about 3 tablespoons each. Place 2 inches apart on prepared baking pans. Bake at 400° for 20 minutes or until puffed and golden.