- Tenderise schnitzel, season and tip them into the flour, egg then finally crumbs. Heat margarine, and schnitzel, saute each side 3-4 minutes, then put them on a serving plate and keep hot in low oven. Add sliced mushrooms to leftover cooking fat and saute for approx. 3 mins, then pour over mixture of water, lemon juice and cornflour and stir until sauce is smooth, and season. Pour sauce over the hot schnitzel, garnish, and serve.