Bronzed Fish Sandwich with Homemade Tartar Sauce and Pickled Onions on a Toasted Brioche Bun

Method:
Thinly slice red onions and add to a jar along with water, vinegar, sugar, salt, black peppercorns, lime juice and garlic cloves, let it sit for a few hours at room temperature and then store in the fridge;
Make tartar sauce by mixing the ingredients above;
Add some olive oil to pan and toast the brioche buns; set them aside;
Pat dry fish and season with salt, pepper, paprika, garlic powder and chipotle powder; sear in olive oil until golden on both sides;
To assemble- add tartar sauce to the bottom bun, lettuce, the seared fish, more tartar sauce, pickled onions and devour;