In a large bowl, stir the ricotta cheese until smooth and creamy.
To the bowl with the ricotta, add the ground beef, Italian sausage, panko breadcrumbs, parmesan cheese, garlic, herbs, and seasonings. Using your hands, gently mix until just combined. Don't overmix, as this can make the meatballs tough.
Wet your hands slightly and form the mixture into meatballs about 1½ inches in diameter (about golf ball size) and place them on a baking sheet.
Heat olive oil in a large skillet over medium heat. Once hot, add the meatballs in a single layer, working in batches if necessary. Don't overcrowd the pan.
Brown the meatballs on all sides, about 2-3 minutes per side, until they develop a nice golden crust.
Once all the meatballs are browned, remove any excess oil and return all the meatballs to the pan. Add the marinara sauce, reduce heat to low, and cover.
Simmer for 15-20 minutes, occasionally stirring gently, until meatballs are cooked through (internal temperature should reach 160°F).
Serve hot with additional grated parmesan and fresh herbs if desired.