Onion Smash Burger

### **Serves 2 (Makes 4 Smash Patties / 2 Double Cheeseburgers)** #### **Ingredients** **For the Burgers:** - 500g chuck beef (around 75/25 lean-to-fat), finely ground or pulsed in a food processor - 1 large white onion, very thinly sliced - 4 slices American cheese (or any processed cheese that melts well) - 2 soft burger buns - Homemade dill pickles (see below) - Yellow mustard - Ketchup - Be