Field Mushrooms filled with cheese

1 medium onions, chopped
1 clove garlic, chopped
1-2 tbsp, olive oil
50g chorizo sausage, diced
150g pack cheese
50g pecan nuts, chopped
Few leaves fresh parsley
4 large field mushrooms with stalks removed
25-50g butter

Preheat oven to 180C/350F/gas4. Fry onions and garlic in oil until tender, stir in all other ingredients including diced mushroom stalks but not whole mushrooms. Lightly smear butter on outside of mushrooms and divide mixture between them. Place in a lightly buttered ovenproof dish and bake for 15-20 minutes.
Serve these as a starter or light supper or lunch dish with salads.