Green Bean Gratin

Ingredients

• 1 kg green beans
• 500 g mixed mushrooms (chanterelles, oyster mushrooms, morels...)
• 2 tbsp butter
• 100 g cheese crackers
• 30 g Butter
• 1 small onion
• 30 g flour
• 250 ml broth
• 250 ml milk
• Salt
• spices (to taste)
• 3 tbsp heavy cream
• 1 egg yolk (for thickening)
• 200 g shredded mozzarella
• 50 g finely grated Parmesan

Instructions

1. 1.

   Peel the onion, halve it and dice finely; sauté in butter. Add flour, stir, lightly brown, then gradually whisk in liquid until a smooth, lump-free roux forms; once ready, add remaining liquid all at once. Bring sauce to a boil, season as desired, and optionally thicken with egg yolk by whisking yolk with some milk and sauce, then quickly adding to hot but not boiling milk.

2. 2.

   Trim the beans, remove any strings if necessary, blanch in plenty of salted water for 5 minutes, drain and shock in ice water.