Step by step
Add oil to the gratin so as to make it grainy but moist. Then add salt and half a clove of crushed garlic
Tips
Do you fancy making a really successful mushroom gratin? Then choose fairly large mushrooms that are also fairly firm, so that they can easily hold the filling.
Trivia
If you don’t want to throw away the stems of your mushrooms, keep them and use them sautéed to make a lovely pasta sauce.