You need 1 ingredient. The key ingredients include: ["1 tablespoon sugar", "2 tablespoons vinegar", "Salt and pepper", "2 finely chopped garlic cloves", "1 tablespoon butter", "1 tablespoon oil (I use canola)", "1 box of cannelloni tubes / par-cooked lasagne sheets", "One large bunch of leeks", "One punnet of mushrooms (I use brown or button mushrooms)", "Ricotta cheese (the consistency must be ""stuffable"")", "Large tin of tomatoes", "Bechamel sauce (at least 2 full cups)", "1 tablespoon minced onion", "3 tablespoons unsalted butter", "1/4 cup all-purpose flour", "3 cups milk", "1/4 teaspoon salt", "white pepper to taste", "nuez moscada", "preparation", "In a sauce pan cook the onion in the butter over moderately low heat, stirring, until it is softened. Stir in the flour and cook the roux, stirring, for 3 minutes.", "Add the milk in a stream, whisking vigorously until the mixture is thick and smooth, add the salt and the white pepper, and simmer the sauce for 10 to 15 minutes, or until it is thickened to the desired consistency.", "Strain the sauce through a fine sieve into a bowl and cover the surface with a buttered round of wax paper to prevent a skin from forming."].
