Place minced beef, egg, breadcrumbs, onions, mustard, oyster sauce, coriander and cumin seeds in a large bowl. Knead and mix well. Add more breadcrumbs accordingly.
Once the breadcrumbs have binded all the ingredients, divide into four generously sized balls. If you are cooking the burgers on the grill, stove-top or BBQ, flatten them so they are easier to cook thoroughly.
Warm up a pan on a medium heat, cook each side for 4 minutes.
If you are popping them in the oven, preheat the oven to 230°C. Then roast the burgers for 25 minutes, until the outside is crispy while the insides are still moist and slightly pink.
Once the burgers are cooked, place the pancetta slices into a shallow frying pan. Cook over a low heat so they become crispy, and then place on a paper towel to drain off excess oil.
Build your burger by topping you patty with onions, avocado slices, a small handful of alfalfa and the crispy pancetta. Plate and serve.