Combine first 4 ingredients in a medium bowl; mix well.
Lightly toast English muffin halves; spread with butter.
Top each muffin half with a heaping 1/4 cup of crabmeat mixture.
Place sandwiches on baking sheet, and broil 6 to 7 inches from heat for 2 to 3 minutes or until hot.
Top each with a slice of cheese; broil until cheese melts.