Sauté the onion in a little oil in a non-stick pan, add the chanterelles and sauté for about 5 minutes. Deglaze with the white wine and let it boil down completely. Pour in the broth and reduce to half. Add the cream and reduce it a little, season the sauce with salt and pepper if necessary.
Toast the bread slices and place in 2 small ovenproof dishes. Fry the ham slices and place them on the bread, spread the mushroom sauce over the ham and cover the whole with raclette cheese. Baked under the hot grill until the cheese has melted. Dust with paprika and serve immediately.