In a large skillet, brown beef over medium heat. Add onion and garlic and cook until wilted. Pour off fat. Add tomatoes and cook until softened. Add pepper, egg, and bread crumbs, stir; reduce heat and simmer 5 minutes, stirring occasionally.
Meanwhile, butter a 1 quart casserole. Arrange okra along the outside with the tips toward the inside and the ends along the outside. Spoon meat mixture into the center.
Bake at 375 degrees F for 30 minutes,or until set. Let stand 10 minutes. Invert onto serving platter; garnish with lemon slices.