Cook onions in 2tbs of oil over medium high heat until they start to turn transparent

Add anchovies, garlic and remaining oil and cook until the anchovies start to melt

Add olives, capers and Roma tomatoes and cook for another 2 mins

Deglaze pot with Madeira

When the alcohol has cooked off from the Madeira, add crushed tomatoes and simmer on low for 20 mins

Turn off heat, stir in parsley and then toss with cooked and drained spaghetti