Preheat the oven to 200°C (400°F), 180°C (350°F) for fan assisted.Heat a tablespoon of olive oil in a frying pan (skillet) over a low/medium heat. Add the onion, garlic and rosemary and sweat until tender and fragrant. Set aside to cool.
Whilst the vegetables are cooling, add the mince to a mixing bowl with the paprika, a tablespoon of grated manchego, salt and pepper.
Add the cooled vegetable mixture to the bowl and use your hands to combine the pork with the seasonings. Divide into 16 even meatballs.
Heat the remaining olive oil in the frying pan and add the meatballs, cooking until browned all over.
Whilst you are cooking the meatballs, add the diced chorizo to a separate oven proof pan over a medium heat, cooking until fragrant and the chorizo has released its oils.
Add the thyme, remaining garlic, tomatoes, balsamic vinegar and stock. Mix well to combine and bring to a gentle boil. Add the meatballs to the pan. Cover with foil and transfer to the oven to bake for 15 minutes.
Uncover the meatballs and scatter over the remaining cheese and return to the oven for a further 5 minutes or until the cheese has melted and the meatballs are completely cooked through.