Heat olive oil In a dutch oven or large skillet.
Add onion and fennel saute until translucent and tender - about 10 minutes.
Add mushrooms, saute for a few minutes.
Add garlic, saute for a minute.
Add sauce, red pepper, olives, capers, oregano, black pepper and anchovies.
Bring to bubbly boil, reduce heat to low and cook covered for about 15 minutes.
Add cooked spaghetti & a bit (approx 1/4 cup) of pasta water to sauce and toss.
Salt to taste. Sprinkle with fresh parsley and loads of freshly grated cheese. Enjoy!