MELT margarine in large nonstick skillet on medium heat. Add rolls, cut-sides down; cook 3 min. or until golden brown. Remove from skillet; set aside.
ADD vegetables and garlic to skillet; cook and stir on medium-high heat 3 min. or until crisp-tender. Remove from skillet; cover to keep warm. Add steaks to skillet; cook 30 sec. on each side or until done, brushing with steak sauce for the last 10 sec.
FILL rolls with Singles, steaks and vegetables.