Finely chopped onion, cut into thin pieces of bacon and peas fried in butter and olive oil, suffocating 5 minutes, occasionally stirring. Pour 1/4 cup (50 ml) of water and stew under a lid for 10 minutes. Add the chopped pieces mushrooms, lemon juice, salt and stew for another 5 minutes. Meanwhile, cook pasta until tender, drain, placed in warmed bowls, pour with mushroom mixture and serve immediately with grated feta cheese.