This is inspired by an Argentinian sandwich, Choripan - which literally translates to chorizo bread. It usually consists of chorizo sausages and chimichurri on bread, with the occasional addition of salsa criolla or pickled onions.
For the chimichurri mayo, add garlic, vinegar, egg yolk, oregano, salt, pepper, and chilli to a jug. Pulse everything together using an immersion blender, then slowly start drizzling in the oil.
Once everything is thick and combined, fold through the chopped parsley and shallot. Set aside
Butterfly the chorizo sausages by slicing them through half way, then flattening out.
Cook in a skillet with a splash of oil and something heavy on top (like a chef’s press) until crispy on both sides and cooked through.
Brush both sides of the bread with a thin layer of butter or normal mayonnaise.
Using the same pan to utilise the chorizo oil, add a knob of butter and your two slices of bread. Turn down the heat to medium low.
Add a generous dollop of the chimichurri mayo to the other sides of the bread, then top with grated cheese. Once the cheese is melting and the bread is turning golden brown, add the chorizo and pickled onions, and form it into a sandwich. Once everything is fully cooked, gooey, and melty, remove from the pan.
Slice in half, serve with more chimichurri mayo, and enjoy!