1. First, make the meatballs. Preheat oven to 200C/180C fan/gas 6.
2. Add the mince, breadcrumbs, tomato purée, egg yolk, basil, OXO cube crushed, salt & pepper into a large bowl. Use your hands to combine all ingredients really well.
3. Roll into 20 even-sized balls about the size of a ping pong ball.
4. Add 2 tbsp olive oil and 25 g butter to a frying pan on a medium-high heat, cook meatballs in batches of 8-10, ensuring they are browned all over. Set aside.
5. In the same frying pan, add 2 tbsp olive oil and 25 g butter to a medium-high heat and brown off the onion for 2-3 minutes. Add crushed garlic and fry for a further 1 minute.
6. Add the red pepper and tomatoes. Add your tin of chopped tomatoes and water, stir and bring to a simmer. Allow to reduce to a sauce consistency.
7. This step is optional but worth the effort as it hides the vegetables and makes a deliciously smooth pasta sauce: Use a handheld blender to blitz the vegetables into a smooth sauce.
8. Return meatballs to the tomato sauce, add a little water if required to bring the sauce just below the height of the meatballs.
9. Allow to simmer for 30 minutes until the meatballs are fully cooked through.
10. You can eat now or cook further in a slow cooker for a more tender flavorsome dish.

For a slow cook option:

1. Transfer everything to a slow cooker and cook on low for 3-4 hours.
2. Garnish with parmesan before serving and serve with pasta.

To make the Meatball Sub:

1. Butter the rolls and place the lettuce in first.
2. Followed by a portion of meatballs and topped with grated cheese which you can melt if you wish.