Heat oven to 350°F. In 1 1/2-quart microwave-safe casserole, combine green beans and 2 tablespoons water; cover. Microwave on HIGH for 9 minutes. Drain.
Meanwhile, melt butter in medium saucepan over medium-high heat. Add onion; cook and stir 3 to 5 minutes or until onion is tender. Stir in flour; cook until mixture is bubbly. Gradually add half-and-half, stirring constantly until mixture boils and thickens. Add cheese; stir until melted. Remove from heat.
Add cheese sauce, water chestnuts, mushrooms, soy sauce and hot pepper sauce to beans in casserole; mix gently. Sprinkle with almonds.
Bake at 350°F. For 25 to 30 minutes or until bubbly.