Make Tzatziki Sauce

1. Mix all ingredients together and chill in refrigerator 1-3 hours to allow the flavors to mingle together

Caramelize Onions

1. Heat 1 tbsp olive oil on high. Add onions and sauté for 5-6 minutes, stirring occasionally
2. Add a pinch of salt and reduce heat to medium, sauté 15-20 minutes more, or until caramelized & golden
3. Set aside to cool

Purée & Combine

1. Purée caramelized onions in a food processor. Add chickpeas and pulse until chickpeas are smashed, leaving some whole for texture. Transfer to mixing bowl
2. Add remaining ingredients except panko bread crumbs and stir until combined Slowly mix in enough panko bread crumbs until the mixture comes together and is no longer sticky
3. Cover & chill in refrigerator for 30 minutes before forming patties

Form Patties & Sear

1. Form patties using a lid from a jar or container
2. Heat 1 tbsp olive oil on high
3. Sear burger 3-4 minutes per side, or until heated through

Assemble

1. Spread tzatziki over a piece of naan
2. Top with lettuce and tomato
3. Serve with mixed greens