Burgers with a Spicy Maple Sauce

Ingredients

• 1 lb lean ground beef
• 1/4 cup quick cooking oats
• 2 tbsp fresh flat-leaf parsley, chopped
• 1 egg
• 1 clove garlic, pressed
• 1 shallot, minced
• 1 tsp Montréal steak spice
• 1/4 cup plain Greek yogurt
• 1/4 cup mayonnaise
• 3 tbsp maple syrup (preferably amber syrup for its rich flavor)
• 1/2 tsp harissa sauce (quantity to taste)
• 1/2 tsp smoked paprika
• 4 burger buns
• 4 slices smoked gouda or your choice of cheese
• A few thin slices of red onion
• Lettuce leaves
• 1 tomato, sliced