A Better Bologna Sandwich

Cook and stir first 4 ingredients in large skillet on medium heat 4 min. or until vegetables are tender, stirring frequently.

Remove from skillet; cover to keep warm.

Cook bologna in same skillet on medium-high heat 1-1/2 min. on each side or until lightly browned on both sides.

Spread cut sides of rolls with mustard; fill with bologna and vegetable mixture to make 2 sandwiches.