Mushroom rarebit with mash & thyme gravy recipe - Recipes - BBC Good Food

Heat oven to 200C/180C fan/gas 6. Put a large pan of water on to boil and salt it well. Boil the potatoes until tender, about 15-20 mins. Drain, return the potatoes to the pan and place over a low heat. Add the butter and milk, then mash until smooth. Remove from the heat and season with salt. Keep warm.

Meanwhile, brush the mushrooms generously all over with oil. Place gill-side up in a baking dish, bake for 15 mins, then remove from the oven. To make the rarebit topping, melt the butter in a saucepan over a medium heat and fry the onion for 10-15 mins until soft and translucent. Add the flour and cook for 1 min. Reduce the heat, then add the Guinness, cheese, mustard and seasoning, stirring until the cheese has melted. Add the eggs and stir constantly until the mixture thickens, about 5 mins, but don't overcook or you'll end up with scrambled eggs. Spoon the rarebit mix into the mushroom caps and set aside.

To make the gravy, heat the oil in a pan over a medium heat and add the onion and thyme. Fry for 10-15 mins until the onion is soft and translucent. Add the flour and cook, stirring, for 2 mins. Add the wine, stock and Marmite, then stir until thick. Simmer for about 5 mins.

Just before serving, heat the grill to high. Place the mushrooms under the grill and cook for a few mins until the rarebit is puffed and golden. Reheat the mash if you need to, place a spoonful on each plate along with a mushroom. Spoon gravy around and over the mash, scatter with thyme and serve.