Heat olive oil in an 8 to 10 inch enameled or stainless steel skillet. Add onions and garlic; cook over moderate heat, stirring often, for 7 to 8 minutes until they are soft but not brown. Stir in spinach and cook, stirring constantly, for 3 to 4 minutes. When all moisture has been boiled away, and the spinach sticks lightly to the pan, transfer tbe mixture to a large bowl. Melt 1 tablespoon butter in the same skillet and lightly brown the beef, stirring constantly to break up any lumps. Add the beef to the onion spinach mixture. Season with salt and pepper. Mix well.
In a heavy 2 to 3 quart saucepan, melt the butter over moderate heat. Remove the pan from the heat and stir in the flour. Pour in the milk and cream all at once, whisking constantly until the flour is partially dissolved. Return pan to the heat (high) and cook, stirring constantly with whisk. When the sauce comes to a boil and is smooth, reduce the heat. Simmer, still stirring, for 2 to 3 minutes longer, or until sauce is thick enough to coat the wires of the whisk heavily. Remove sauce from the heat; season with salt and pepper.
Preheat oven to 375 degrees. Place a tablespoon of filling in each piece of boiled Manicotti pasta. Pour just a little of the tomato sauce into two 10x14 shallow baking dishes. Lay the cannelloni side by side in one layer on the tomato sauce. Pour the white sauce over it and spoon the rest of the tomato sauce on top. Scatter in 4 tablespoons grated cheese and dot with 2 tablespoons butter. Bake until bubbly; slide under broiler about 30 seconds. Serves 12.
From <A Taste of Louisiana>.
