In a small saucepan melt butter with 1 teaspoon olive oil. Sauté the onion, bell pepper, celery and garlic over low heat until soft.
In a small bowl whisk the flour and milk together. Pour this into the vegetables, stirring constantly until the mixture bubbles and thickens. Season to taste with coarse salt and ground black pepper. Set aside.
Cook rice on top of the stove or in a rice cooker. Measure out one cup of rice and add 2 cups water. Bring to a boil, turn down the heat and cover the pan; simmer for 25 min.
Clean off the mushrooms with a wet paper towel. Sauté the mushrooms in butter and olive oil until light brown. Set aside.
Set the oven to 350°. Sauté the chopped chicken in olive oil until cooked through. Set aside.
In a medium size bowl add: cooked rice, sautéed mushrooms, cooked chicken, mayonnaise, water chestnuts, milk, salt and white sauce. Mix thoroughly.
Pour into a buttered 9x13 casserole and garnish with slivered almonds on top. Sprinkle generously with paprika. Bake 30 min.
Use canned mushrooms. Substitute 2 cans cream of celery soup for white sauce.
Serve with: Fresh or frozen peas, broccoli, asparagus or zucchini. Hot Rolls. Variations: Use canned mushrooms. Substitute 2 cans cream of celery soup for white sauce.