Sauce mornay is a béchamel sauce with grated cheese
- Combine both grated cheeses.
- In a saucepan, combine the sauce béchamel and the cayenne.
- Stirring constantly, heat the sauce until it comes to a simmer.
- Remove the saucepan from the heat and stir in the grated cheese.
- Taste for seasoning and adjust with salt and pepper if necessary.
- If not served immediately, you may dot the surface with butter to prevent a skin from forming.