Preheat the oven to 350° F (175° C).
Grease a muffin tin thoroughly with butter.
Chop scallions and chorizo and add to the bottom of the tin.
Whisk eggs together with seasoning and pesto Add the cheese and stir.
Pour the batter on top of the scallions and chorizo.
Bake for 15- 20 minutes, depending on the size of the muffin tin.