Peel onion and garlic. Cut some wafer-thin rings from the onion to garnish. Finely dice the remaining onion. Press the garlic through a garlic press. Heat butter in a small pot. Fry the onion and garlic until transparent. Add curry and turmeric.
Add flour and sauté. Add stock and whipped cream while stirring constantly. Season to taste with lemon juice and salt. Wash coriander, dab dry and pluck leaves, except some for garnishing, from the stalks. Chop the coriander finely, sprinkle into the sauce and fold in. Garnish with onion rings, coriander and lemon peel strips