Heat the oil in a large saucepan. When the oil is hot, sauté the onions until they are golden brown.
On my stove, it takes about 8 ½ minutes.
After you have browned the onions, add the crushed tomatoes to the saucepan. Stir in the oregano, basil, salt and pepper. Simmer the sauce for 1 hour.
Dice the pancetta into 1/4 inch cubes.
About 20 minutes into the sauce simmering process, add the diced pancetta into a large frying pan. Cook until the fat renders and the pancetta crisps up. Remove the pancetta from the pan, reserving the rendered fat.
Add the mushrooms and hot pepper flakes into the frying pan with the reserved pancetta fat. Saute over medium heat until the mushrooms are golden.
On my stove, it took approximately 15 mins, but this will differ for everyone.
Add the vodka slowly to the mushroom mixture and simmer for 5 minutes to cook off the alcohol.
Add the heavy cream to the mushroom / vodka mixture and bring to a simmer (this took
approximately 5 min on my stovetop).
Pour the cream mixture into the tomato puree and stir. Keep the sauce warm while you cook the pasta.
Add approximately 1 tbsp of kosher salt to 6 quarts of water and bring the water to a rolling boil. Add the pasta to the water and cook uncovered until the pasta is al dente (follow the cooking directions on your box of pasta for the al dente recommendation).
Drain the pasta well.
This step is extra – we didn’t take this step on the day we had leftovers, but we did it on the first night – Melt the remaining 4 tbsp of butter in a large skillet. Stir in the pasa to glaze and then add the parmesan cheese. Mix thoroughly.
Stir in the about 1/3 of the sauce and 2/3rds of the crispy pancetta with the pasta. Top each plate with some additional sauce and pass the remaining sauce and additional cheese at the table. This last step is up to you.
We stirred in 1/3 of the sauce and added just a little bit to the top of each of our plates. We saved the rest for leftovers!