Combine sugar, almonds, and margarine in food processor; pulse 10 times or until nuts are finely chopped. Press mixture into a 7-inch circle on a baking sheet coated with cooking spray. Broil 1 minute until bubbly but not burned. Remove from oven, and let stand for 5 minutes. Gently turn toffee over, using a wide spatula, and broil an additional minute. Remove from oven, and let cool. Break the toffee mixture into 1/2-inch pieces.
Note: Watch toffee closely as it broils - let it bubble, but not burn.