Step 1Heat the pressure cooker insert and melt 1 tablespoon butter. Add the prosciutto and brown, stirring frequently.
Step 2Add the onion, celery and carrot, oregano and fennel and continue to cook until lightly caramelized, stirring frequently. Add the garlic and cook until aromatic. Strain the vegetables to a bowl, leaving the fat in the insert.
Step 3Add the remaining butter and brown the ground beef, pork and veal, stirring frequently and breaking up any lumps. Stir in the tomato paste.
Step 4Add the red wine, stirring to scrape up any flavorings from the bottom of the pan. Bring to a simmer, then stir back in the vegetables.
Step 5Stir in the salt, black pepper, then stir in the beef broth. Stir in the tomatoes and cream. Seal the pressure cooker and bring to high pressure. Cook at high pressure for 8 minutes.
Step 6Release pressure naturally (about 10 minutes, depending on the cooker) and carefully remove the lid. Skim the fat if desired and stir. Taste and adjust the seasonings if needed, and add a little extra cream, if desired. This makes about 3 quarts Bolognese sauce. Stir in the parsley before serving.