Brush the inside of the top and bottom halves of the French roll with 1 Tbsp. of olive oil. Place the oiled side down on a heated flat griddle. Grill until golden brown. Place the bottom of the roll on a warmed serving plate.
Spread 2 oz. of red pepper jelly on the inside of the bottom half of the bun. Place the broccoli rabe on top of the jelly. Place 2 oz. of sliced white cheddar on top of the broccoli rabe. Place under a heated salamander to melt the cheese.
Spread 1 oz. of the mayo to the top half of the bun, add the top of the bun to the sandwich and serve.