Beef Patties:
Sauté some onions and fresh mushroom with salt, lots of black pepper and worcestershire sauce
Let them brown well
Remove from pan
Blend
Leave aside so they cool down

Patty mix:
500 grams finely minced lean beef
2 tsp mustard
1 minced garlic
Some salt and pepper
The mushroom/onion mix
Mix all together
Form into patties and place in the fridge for 10 minutes
Grill for around 2 minutes on each side
Place cheese on the hot side the patty so it melts

Barbecue sauce:
Combine in a pan: 1 cup ketchup, 1/2 cup water, 1/4 cup apple cider vinegar, 2.5 TBS light brown sugar, 2.5 TBS sugar, 1/4 tsp of each: black pepper, ground mustard, 1/2 TBS of each lemon juice and Worcestershire sauce
Bring to boil, reduce heat let simmer for 1 hr stirring occasionally

Baked Potato:

500 grams baby/small potato cut into wedges
2 TBS olive oil
Some black pepper, salt and paprika
Bake in an oven at 200 degrees for around 30 mn

Layer it up:
Beef/cheese
Lettuce
Tomato
More grilled onions and mushrooms
Serve with grilled potato and barbecue sauce/mustard/ketchup