For the meatballs, prepare quinoa in boiling salted water according to the instructions on the packet. Then let it cool down a little. Peel onion and garlic and dice finely. Heat 1 tablespoon of oil and fry the onion and garlic until translucent, remove from heat. Pour beans into a sieve, rinse and drain well. Grate cheddar roughly. Crush the beans finely with a fork.
Knead the prepared ingredients, egg and crumbs, season with salt and pepper. Form the mixture into 4 flat meatballs and chill.
Peel the sweet potatoes and cut them lengthwise into thick chips. Place in a large bowl, season with salt and drizzle with 4 tablespoons of oil. Mix the potatoes and spread them on a baking tray covered with baking paper. Bake in a preheated oven (electric cooker: 225°C/ convection oven: 200°C/ gas: see manufacturer) for approx. 30 minutes. After about 15 minutes, turn the chips.
Mix salad cream and mustard. Drain onions and cut into rings. Heat 2 tablespoons of oil in a frying pan. Fry the meatballs for about 6 minutes, turning them in between. Cover with 1 slice of mountain cheese each. Close pan with lid and let cheese melt briefly. Season chips with paprika. Cut the rolls in half horizontally. Cover the lower halves with salad cream, meatballs, onions and chips, place the upper halves of the roll on top. Add the rest of the fries.