Easy

Olive oil

Peel and slice the mushrooms. In a frying pan with a drizzle of oil, cook the mushrooms.

Grate the mimolette. Take a tortilla on a half garnish with pesto, mimolette mushroom then close. Renew the operation with all the Tortillas.

In a hot frying pan, brown the Tortillas on each side until the mimolette melts. 
You can cut the quesadillas into wedges if you wish to serve.