Swiss Mushroom Burgers

Bahan-bahan (4 porsi)

• 4 + BIG mushrooms - like portobello, BBQ flat mushrooms ((20% larger than buns, or buy multiple per burger) (Note 1))
• 30 g / 2 tbsp unsalted butter
• 2 g arlic cloves (, finely minced)
• 1/2 tsp each salt and pepper
• 1/2 tbsp olive oil
• 4 slices swiss cheese ((or any other cheese slice of choice))
• 3 onions (, cut into 0.7cm / 1/3" rings)
• 1 tbsp olive oil
• 1/4 tsp each salt and pepper
• 2/3 cup mayonnaise (or sour cream + pinch of salt)
• 2 tbsp ketchup
• 1 - 3 tsp Sriracha ((adjust spiciness to taste))
• 4 buns or rolls ((I like brioche))
• 8 - 12 lettuce leaves
• 2 tomatoes
• French fries
• Baked potato wedges