Mix all the ingredients for the burger patties together. If you're wondering why I used minced onions, well....my mother always used minced and also because grated might be too wet. I used garlic powder in case raw garlic might be too acrid for this burger.
Leave it to sit in the fridge for at least 2 hours or you can do this the night before for the flavours to infuse together.
Shape your patties. Make the middle thinner than the sides so when it cooks it will be levelled and cook evenly.
Cook your beef-pork patties in a pan with some olive oil. 1 min on first side and 2-3 mins on the other side on medium-low heat.
When the patties are done, place the cheddar cheese slices on top of the patty and cover it with a lid. Turn off the heat.
Butter and toast your buns. Spread some mustard mayo on the bottom bun. Put the burger-cheese patty on the bun.
Top with tomatoes, onions, BBQ sauce and lastly salad leaves. Cover with the other half of the bun.
Eat with chips or fries.
Condiments are really preferential, you don't have to follow exactly what I used if you don't have say, mustard or BBQ sauce.