Stack a few slices of the prosciutto together at a time. Roll the slices up and cut thin slices from there. Using your hand separate the pieces up a bit after cutting.
Heat a large pot, over medium low heat, and add in about ¼ cup of olive oil. Add the prosciutto and brown until crisp. Remove the prosciutto with a slotted spoon and place aside.
To the oil go ahead and add the onion, garlic, oregano and a little salt and pepper. Cook until softened.
Add in the pureed tomatoes and simmer, stirring occasionally, for about 30-45 minutes.
Lower the heat at the end of the cooking time and stir in the light cream and peas. Cook for a few minutes, until the peas are warmed through. Cover.
Cook the tortellini to al dente according to package. Drain and toss with the sauce. Serve the crisp prosciutto over top.