Burgers with a Spicy Maple Sauce - Maple from Canada

Ingredients

• 1 lb lean ground beef
• ¼ cup quick-cooking oats
• 2 tbsp flat-leaf parsley, chopped
• 1 egg
• 1 garlic clove, pressed
• 1 shallot, minced
• 1 tsp Montréal steak seasoning
• ¼ cup Greek yoghurt
• ¼ cup mayonnaise
• 2 tbsp + 1 tsp pure maple syrup (preferably amber syrup for its rich flavour)
• ½ tsp harissa sauce
• ½ tsp smoked paprika
• 4 burger buns
• 4 slices of smoked gouda or your choice of cheese
• A few thin slices of red onion
• 1 tomato, sliced
• Lettuce leaves, to garnish