Finely dice the 2 onions and mix with the 500 g minced beef. Season with salt, pepper, paprika powder, chilli powder, and Worcester sauce. Mince 2 cloves of garlic and add to the mixture. Mix thoroughly and form 2 even burger patties. Refrigerate until ready to cook. Heat a grill or large skillet to medium-high heat and cook each patty for 10 minutes on each side until the internal temperature reaches 71°C (160°F). Top each patty with 1 slice of cheese in the final minute to melt.
Fry the 8 slices of bacon over medium heat for 6-8 minutes, turning occasionally, until crispy. Slice the tomato and rinse the 4 sheets of iceberg lettuce. If using cucumber, slice it. Toast the 2 hamburger rolls lightly if desired. On each roll, layer the bottom bun with lettuce, tomato slices, cooked patty with melted cheese, bacon, fried onions, and sliced cucumber if desired. Top with ketchup, mustard, or BBQ sauce as preferred, then place the top bun.