To begin, combine the ground beef, pork, and lamb in a large mixing bowl. Mix gently with your hands to distribute evenly. Avoid over mixing to keep the meat tender. Proceed to add aromatics.

Stir in the grated onion and finely chopped garlic. Mixing onions into the meat helps lock in moisture while adding sweet sharpness. Continue with seasoning.

Sprinkle in paprika, black pepper, and salt. Add baking soda and sparkling water, then mix until just combined. The baking soda helps loosen the texture, while sparkling water gives lightness. Move to marination.

Cover the bowl with cling film and refrigerate for at least 1 hour, preferably overnight. This rest allows flavours to deepen and the meat to firm. Transition to shaping patties.

Divide the mixture into four equal portions. Shape each into a large, flat patty about 1.5 cm thick. Press lightly in the centre to prevent doming during cooking. Prepare the grill next.

Preheat a charcoal grill or heavy griddle pan to medium to high. A charcoal grill is most authentic, lending smoky flavour. Ensure the surface is well oiled to prevent sticking. Move to cooking.

Place the patties on the hot grill. Cook for 4–5 minutes per side until golden brown with charred edges, ensuring the inside remains juicy. Do not press down while cooking as it releases juices. Move to resting.

Transfer the cooked patties to a plate. Let them rest for a few minutes to allow juices to redistribute. Transition to preparing accompaniments.

Place each patty inside warm lepinja or pita. Add kajmak, sliced onions, and a spoon of ajvar. For presentation, serve with a side of fresh salad or roasted peppers for a true Serbian meal.