Ingredients

• 1 tablespoon oil
• 1 red onion, peeled and finely sliced
• 1 teaspoon minced garlic
• 12-16 flat portobello mushrooms
• 2 sheets pre-rolled puff pastry, defrosted
• Mustard and sour-cream sauce
• 150 gram tub sour cream
• 2 tablespoons herb, Dijon or wholeseed mustard

Method

1. Heat the oil in an ovenproof pan. Cook the onion and garlic for 5 minutes over a low heat until they are just softened. Arrange the onion evenly over the pan. Place the musrhooms, stalk side down, into the pan, slightly overlapping them.
2. Lay pastry sheets on top of each other and roll out together. Place on top of the mushrooms, tucking edges into the pan.
3. Bake at 200ºC for 20-25 minutes until the pastry is golden. Stand a minute or two before turning upside down on to a platter to serve. Dust with chopped parsley to serve, if wished. Make the sauce by mixing together the sour cream and mustard and serve with the tart. Accompany with a side salad.