1Peel the onions and cut into thin rings. Heat the oil in a pan, saute onions over low heat for about 10 minutes. Braise. Stir frequently to prevent over browning.
2Season the onions with salt and pepper. Cut the bacon into thin strips or cubes and lightly brown in same pan, then drain on paper towels. Free the cheese from the bark and also cut into cubes. Mix bacon and cheese with sour cream.
3Heat up raclette grill or the stove/oven. Distribute a the onion rings in the pan, cover with bacon-cheese mixture. Place under raclette grill or broiler/oven and cook, until the cheese has melted and lightly browned.