To make your marinade, crush up the cumin, fennel seeds and cloves in a pestle and mortar and mix with the paprika, orange zest and juice, thyme, garlic, ketchup and balsamic vinegar. Season the pork fillets with salt and pepper, then toss them in most of the marinade until completely coated. Feel free to marinate for half a day, but at least an hour. If you have metal or wooden skewers, lay the fillets side by side and skewer them together about 2.5cm/1 inch apart.
When you’re ready to cook, simply put the meat on to a barbecue or under a hot grill for 15 to 20 minutes or until nicely charred. Every time you turn the meat, brush it generously with the leftover marinade so you build up a sticky, blackened glaze. When they’re done, put the fillets on a big platter and allow to rest for 5 minutes. Slice the meat between the skewers, or just slice each fillet in half, and sprinkle over some chopped coriander or squeeze over some lemon juice if you fancy.