Preheat the oven to 450 degrees. In a deep, oven-proof skillet, melt the butter over medium-high heat. Add the onion and rice. Stir until onion is translucent and rice is opaque, about 2 minutes. Add the lemon juice and cook until evaporated, stirring constantly. Pour in the broth and 1 cup water. Remove from heat.
Cover with a large sheet of foil, pressing it down to touch the surface of the liquid. Seal the foil around the rim of the pan. Cover pan with a tight lid. Bake the risotto 45 minutes.
Meanwhile, boil 1 cup water in a medium saucepan. Add the asparagus and cook 2 minutes. Transfer the asparagus to a bowl. Add the shrimp to the pot. When pink and curled, add them to the bowl. Place the mussels in the pot, cover and cook until opened, about 2 minutes. Drain and set aside.
Remove the risotto from the oven and place it on top of the stove. Slowly peel off the foil, starting from the side furthest from you. Mix in the cheese, asparagus and shrimp.(Use oven mitts to prevent steam burns.) Season to taste with salt and pepper. Serve in shallow soup bowls or plates, using the mussels as garnish.
Makes 6 servings.
Per serving: 293 calories, 7 g. total fat (4 g. saturated
39 g. carbohydrate, 17 g. protein, 2 g. dietary fiber, 493 mg. sodium.