Hamburger with Appenzeller® | Cheeses from Switzerland

Ingredients

• 600 g ground meat (beef or chicken, according to taste)
• 2 tbsp ketchup
• 4 slices Appenzeller®
• 1 red onion sliced into rings
• A few lettuce leaves
• 4 small hamburger buns
• 2.5 dl milk
• 1 dl water
• 50 g butter
• 400 g wheat flour
• 100 g spelt flour
• 12 g dry yeast
• 1 tsp salt
• 2 tbsp sugar
• 1 egg
• 1 tbsp flour