Product Recall: One SKU of Velveeta Cheesy Skillet Singles Due to Undeclared Soy: Click Here
COMBINE onions and 1 Tbsp. dressing; let stand 10 min.
MEANWHILE, cook mushrooms in remaining dressing in skillet on medium-high heat 10 min. or until tender.
SPREAD toast slices with mayo, then mustard. Fill with spinach, onions, meat, mushrooms and cheese to make 2 sandwiches.