Grape Salad

2 Tbsp. melted butter
2 Tbsp. flour
1 cup milk
1/2 cup pecans (optional)
1 large can pineapple chunks, drained
2 lbs. seedless grapes
1 dozen large marshmallows or one small pkg. mini-marshmallows
Make white sauce by mixing 2 Tbsp. melted butter and 3 Tbs-p. flour. Add 3/4 cup milk. Stir until smooth, then add rest of milk and marshmallows. Remove from heat and cool.
Mix the grapes, pineapple, and nuts together. Pour the cooled white sauce over the grape mixture & chill in refrigerator.