To prepare a spinach lasagna casseroles recipe, you will first need to prepare your ingredients. You will need: 1 1/2 cups shredded spinach 1/2 cup ricotta cheese 2 tablespoons olive oil 1 tablespoon melted butter 1 teaspoon kosher salt 1/2 teaspoon cayenne pepper Instructions: Preheat the oven to 350 degrees F (180 degrees C) and grease an 8 x8-inch baking dish with non-stick cooking spray. Toss the spinach with the remaining ingredients and bake the dish for 20 to 25 minutes or until the cheese is bubbly and the mixture is heated through.