Caramelised mushrooms and onions

Heat butter and olive oil in a cast iron/ heavy bottomed skillet.Add onions and saute on medium high heat till they turn brown and are caramelised.

Add green chillies,mushrooms,salt and garlic. Saute on high heat till all the water from the mushroom is absorbed.

Add apple cider vinegar, stock and rosemary; ontinue to saute on high heat till the mushrooms caramelise and all the liquid is absorbed.

Remove from heat and serve on toasts.