Peel onions; place in a large saucepan. Cover with water; sprinkle with 1/2 teaspoon salt, and bring to a boil. Reduce heat, and cook 20 minutes or until tender. Drain well, and place onions in a 2-quart casserole.
Melt butter in a heavy saucepan over low heat; add flour and remaining salt, stirring until smooth. Cook 1 minute, stirring constantly. Gradually add milk; cook over medium heat, stirring constantly, until thickened and bubbly. Stir in hot sauce. Pour cream mixture over onions. Sprinkle with almonds.