Preheat the oven to 180°C (356°F). Finely chop the ham, grate the cheese, and cut the spring onion into thin rings. Take a standard (non-stick) 12-hole muffin tray and coat it generously with softened butter or lard. Set aside.
In one bowl add dry ingredients: flour, baking powder, salt, thyme, and sweet paprika, and whisk well. Whisk kefir, eggs, and melted (but not too hot) butter in another bowl.
Pour the wet ingredients into the bowl with dry ones and stir with a spatula until just combined. Add most of the ham, cheese, and spring onion reserving some of it for sprinkling on top of the cornbread muffins before baking and stir again.
Spoon the batter evenly among all 12 holes filling them right up. Sprinkle with the rest of the cheese, ham, and spring onions. Bake for 15-20 minutes.
Check the doneness with a toothpick, it should come clean when muffins are baked. Take them out of the oven, leave for 1-2 minutes in the baking tray and carefully remove from the muffin tray. You need to do this right away otherwise the bottom can become soggy.