Put onion, carrot, celery, garlic, oregano and red pepper flakes into a food processor and pulse 10 times - you want the mixture to be a fine chop, not a puree. Transfer to a bowl.

Put mushrooms in food processor and pulse about 6-8 times. Add in meat and pulse until combined, about 8 more pulses.

Heat butter and oil in a dutch oven, heavy pot or pan (I like to use my Creuset).

Saute vegetable mixture for about 5 mins. Stir often and don't let brown.

Add paste and soy sauce and mix well for about 1 minute.

Add in mushroom and meat mixture and cook for about 10 minutes until liquid is evaporated and meat starts to sizzle.

Add the tomatoes and juices and simmer, uncovered for another 30 minutes.

Add in fish sauce and parmesan and season with salt and pepper to taste.

While sauce is cooking, make pasta according to package directions.

Divide pasta among 4 plates, top with sauce and sprinkle with parmesan and fresh herbs.