Grill brats according to package directions (Cook, covered on the grill over low-medium heat, for 15-20 minutes until sausage is browned and the internal temperature is 160°F, turning links often). OR Spray skillet with cooking spray. Cook brats over medium-high heat until browned, about 5 minutes, turning often. Reduce to medium-low heat, add 1/2 cup water, cover and simmer for 12 minutes until the internal temperature is 160°F.

Brush onion slices with oil and grill over medium heat for 3 to 4 minutes per side or until crisp-tender and golden.

Cut onion slices in half; place in a large bowl.

Grill whole peppers until skins blister, about 3 to 4 minutes.

With tongs, rotate peppers a quarter turn. Grill and rotate until all sides are blistered and blackened.

Immediately place peppers in a bowl and cover or cool for 30 seconds, place in a large resealable plastic bag and seal; let stand for 10 minutes.

Peel off and discard charred skin. Remove seeds. Slice peppers into ¼-inch strips; place in bowl with onions.

Add cracked pepper to onions and peppers; toss gently.

Place one brat in each roll. Top with pepper and onion mixture. Serve hot.