Stir together first 5 ingredients. Spread mixture evenly over cut sides of muffin halves; sprinkle evenly with cheese.
Broil 5 inches from heat 2 to 3 minutes or until cheese is melted. Serve immediately.
*2 (6-ounce) cans lump crabmeat or 2 (6-ounce) cans solid white tuna in spring water, drained, may be substituted.