Add the ground pork, paprika, lemon zest, and a good pinch of salt and pepper to a mixing bowl. Finely chop the rosemary and garlic. Add the rosemary and garlic to the bowl and mix everything well with your hands.
Heat a tablespoon of olive oil in a skillet over a medium/high heat. Divide the meat mixture into 16 even-sized portions and roll each portion into a ball. Add the meatballs to the skillet and cook until browned all over. Remove from the skillet with a slotted spoon and set to one side.
Add the half tablespoon of olive oil to the skillet. Roughly dice the chorizo. Add the chorizo to the skillet and pan-fry over a medium heat until browned all over and releasing its oils. Remove from the skillet with a slotted spoon and set aside with the meatballs.
Finely dice the onion and add to the skillet. Sweat gently for a few minutes until tender and fragrant. Add the chopped tomatoes, stock, salt and pepper. Stir well to combine and bring up to a boil.
Reduce the sauce to a simmer. Return the meatballs and chorizo to the skillet, stir well. Continue to simmer for a further 10 minutes or until the sauce has reduced down and the meatballs are cooked through. Serve hot with your preferred Keto sides.