Pineapple burger with Caribbean BBQ sauce

Ingredients

• 4 bananas, mashed
• 1 tbsp butter
• 2-3 onions, diced
• 200 ml ketchup
• 2 tsp chilli powder
• 2 tsp salt
• 1 tsp pepper
• 2 tbsp Worcester sauce (soy sauce)
• 120 g sugar, brown
• 500 g minced meat (beef or mixed)
• Salt
• Pepper
• 2 crushed garlic cloves
• 4 brioche burger buns
• 2 red onions
• some lettuce leaves
• 1 large tomato
• 4 slices of cheese (as desired)
• 4 slices of pineapple (can)