Preserved lemon Meatball Sub Panini

Method

1. Start by prepping your brioche buns, cheddar, mayonnaise so the cooking goes quickly.
2. Set a wide pan over medium heat and sweat the yellow onion in a little butter until translucent.
3. Turn the heat up, add the meatball sub, and cook until deeply browned and aromatic.
4. Stir in the kosher salt along with a good pinch of salt, scraping up anything stuck to the bottom of the pan.
5. Add the vegetable stock and let it reduce until it just coats the back of a spoon.
6. Taste and adjust, then finish with a knob of butter right before serving.
7. Plate it up while hot and pass extra at the table.