Put the bell pepper, carrot, celery, onion and garlic in a food processor. Add a few tbsp olive oil and pulse until the veg are evenly minced. Pour the contents into a medium pan on medium-high heat. Add a pinch of salt and a few grinds of black pepper and fry for 5 or 6 minutes, until the veg are no longer wet and are just starting to caramelize. Transfer the veg to a large mixing bowl to cool.

Add the pork, mint, and panko to the cooled veg. Add a few pinches of salt and several grinds of black pepper and knead with your hands to bring it all together. Don't overmix. If the mixture seems wet, add more panko a little at a time. The final mix should be moist but not so wet it sticks like glue to your fingers. Form meatballs a little larger than golf balls. You should be able to make about 12. Leave them uncovered in the fridge for 15 minutes.

Add a good splash of veg oil to a large nonstick pan on medium heat. Carefully lay in the meatballs. Let fry for 15 to 20 minutes, rotating often. To check doneness, insert a thermometer into the biggest meatball. It should read 160 F. Remove the meatballs to a paper-towel lined plate to drain.

In a bowl, mix together the tzatziki ingredients along with a good pinch of salt and several grinds of black pepper. Serve with the meatballs.