Prepare the Salsa Verde: If using fresh tomatillos and jalapeños, place them on a baking tray and grill for 5-7 minutes, turning once, until they are soft and slightly charred. This step deepens their flavour. If using tinned, you can skip this. Add the tomatillos, jalapeños, chopped onion, garlic, fresh coriander, lime juice, and chicken stock to a blender. Blitz until you have a relatively smooth sauce.

Season the Chicken: Pat the chicken breasts dry with a paper towel. This is key for getting a good sear. Season both sides generously with the cumin, oregano, salt, and black pepper.

Sear the Chicken: Heat the olive oil in a large, heavy-bottomed frying pan or skillet over a medium-high heat. Once the oil is shimmering, carefully place the chicken breasts in the pan. Be sure not to overcrowd it; cook in two batches if necessary. Sear for 4-5 minutes per side, until a deep golden-brown crust forms. The chicken won't be cooked through at this point. Remove the chicken from the pan and set it aside on a plate.

Simmer the Sauce: Lower the heat to medium. Pour the blended salsa verde into the same pan. Let it bubble gently for 3-4 minutes, scraping up any browned bits from the bottom of the pan with a wooden spoon. This adds so much flavour!

Combine and Cook: Return the seared chicken breasts to the pan, nestling them into the sauce. Reduce the heat to low, cover the pan with a lid, and let it simmer for 10-15 minutes, or until the chicken is cooked through and the internal temperature reaches 74°C (165°F). I find that simmering gently is the secret to keeping the chicken moist.

Melt the Cheese: Once the chicken is cooked, sprinkle the grated cheese evenly over the top of each breast. Place the lid back on for another 1-2 minutes, or until the cheese is gloriously melty and bubbling.

Rest and Serve: Remove the pan from the heat and let it rest for 5 minutes before serving. This allows the juices in the chicken to redistribute. Serve hot, with a spoonful of the extra sauce from the pan.