Turn on the Sauté function on the Instant Pot and heat the olive oil, if using. Add the ground beef and cook until no longer pink (about 7-8 minutes), breaking it up into smaller pieces. Discard the excess oil, if needed (tip: you can use tongs and paper towel to soak it up, rather than draining it from the insert). Add the onion and garlic and sauté another couple minutes until they are starting to soften and become fragrant. Turn off the sauté function.
Add a small amount of the broth and deglaze the bottom of the insert (using a spatula, scrape up any brown bits that are stuck). Add the remaining broth, marinara sauce, diced tomatoes, basil, parsley, onion powder, oregano, red pepper flakes, and dried rosemary. Add the broken lasagna noodles and push them down into the liquid until just submerged (do not stir). Put on the lid, set it to sealing and cook on Manual high pressure for 6 minutes. It will take about 20 minutes to come to pressure.
At the end of pressure cooking time, quick release the pressure. Stir in the balsamic vinegar, ricotta and parmesan. Season with salt and pepper to taste, then sprinkle mozzarella on top. Set the Instant Pot lid askew on the pot to allow the mozzarella to melt. Serve immediately, garnished with fresh parsley, if desired.
