Add 2 Tbls of olive oil to pan. Add spring onion to pan and cook until translucent for about 2 minutes.
add wine to pan and reduce until alcohol has evaporated and most of the liquid has been absorbed by the onions.
add the porcini mushrooms to the spring onion mix. Add a splash (2-4 Tbls)of cream depending how creamy you want the pasta. Reserve a few to garnish with at the end
Stir in the walnuts
add the tomatoes and squeeze of lemon. Check seasoning add salt and pepper to taste.
Serve on a bed of linguine and garnish with thyme and parmesan