Step 1

In a small bowl, stir together the honey and harissa until combined. Using a spoon or butter knife, spread the sauce on both sides of the rolls.

Step 2

In a large skillet over high heat, heat the oil until it shimmers. Add the slabs of halloumi and sear until browned, 1 to 2 minutes. Flip and sear on the other side, about 2 minutes. Transfer a piece of cheese to the sauced bottom of each roll.

Step 3

Add the onion and peppers to the skillet and cook, stirring occasionally, until softened and deeply browned in spots, about 7 minutes. Remove from the heat. (To cook the cheese, onions and peppers on a grill, see Notes.) Divide the peppers and onions between the sandwiches, add the top roll to each sandwich and serve, with any extra peppers on the side.