Cook the Book: Beet Green Gratin

INGREDIENTS

• 1 tablespoon unsalted butter, plus extra for the pan
• 12 ounces mushrooms, sliced
• 2 cloves garlic, minced
• 1 pound beet greens cleaned, stemmed, and roughly chopped
• 1/2 teaspoon kosher salt, plus additional to taste
• Freshly ground black pepper, to taste
• 4 large eggs, lightly, beaten
• 1 cup ricotta cheese
• 1 ounce Parmesan cheese, freshly grated or ground
• 2 ounces butter crackers, crumbled