Set a medium skillet over medium heat, and once it’s hot, swirl in a splash of olive oil. Sauté the onion until it’s soft and translucent, about 5 minutes. Stir in the peas, garlic, and harissa, and cook for 3 to 5 minutes more, smooshing the peas with the back of a spoon to break them down a bit. Scrape into a mixing bowl and cool for about 5 minutes.

Crack the egg into the bowl and beat it lightly with a fork. Stir in the halloumi, panko, herbs, and arrowroot powder, then shape into 8 patties. The mixture will seem a little loose, and to make it slightly easier to shape, you can pulse it a few times in a food processor. But even without the food processor, the burgers will hold their shape once cooked.

To pan-fry them: Preheat a dry nonstick or seasoned skillet over medium-low heat. Carefully add as many patties as will comfortably fit. They should quietly sizzle in the pan—adjust the heat if necessary. Cook until browned on the bottoms, 4 to 5 minutes, then flip and repeat on the other side.

To bake them: Arrange the burgers on a parchment-lined baking sheet and cook in a preheated 350°F oven for 25 to 30 minutes, flipping them over halfway through, until lightly browned and firm in the centers.

Serve on buns with your favorite toppings, or over salad, or for breakfast, or however you please. The cooked burgers will keep for a few days in an airtight container in the refrigerator. Reheat them in a dry skillet over low heat.