Preheat oven to 400°F. Grease muffin tin or line baking sheet.
Add egg, milk, oil, flour, and salt to blender. Blend until smooth.
Pulse in cheeses briefly.
Pour batter immediately into muffin wells (¾ full).
Bake 15–20 minutes until puffed and golden.
For traditional method: heat milk and oil, pour over flour/salt in bowl.
Stir, then beat in egg and cheese.
Scoop into balls and bake.
Serve warm.
