2) Cut the brioche into about 1 to 1.5cm thick slices and then use a small glass to cut out as many circles as possible, about 7.5cm in diameter, from each slice. Place the bread "buns" in an airtight container until ready to use so that they stay moist and soft.
For the burgers:
1) Preheat the griddle or grill. Combine the lamb, cumin, cinnamon, coriander, salt, pepper and garlic in a mixing bowl and work together until they are fully incorporated.
2) Using a small ice cream scoop, scoop the mixture into little balls about 2 to 3cm big and place them on a greaseproof paper-lined baking pan. Using your hands, flatten the burgers to about 1cm thick and just a few centimetres in diameter.
3) Once the griddle is hot, add the burgers and cook, about 2 to 3 minutes per side or until fully cooked through; cook time varies based on how hot your griddle is.
4) Place the cooked mini burgers on top of the cut brioche and add a piece of lettuce and a tomato slice. Top with a dollop of the lemon yoghurt sauce and serve.