In a wide bowl add thick curd or yogurt, chilli powder, cumin powder and salt to taste.
Add in diced onion, yellow bell pepper, red bell pepper and paneer to the curd spice mixture.
Mix well until masala coats onto the veggies and paneer. I wrap the bowl and refrigerate it overnight. I always love my chicken, fish, paneer, veggies tikkas to marinate overnight.
Transfer the paneer and veggies to a baking tray and brush some oil all over the pieces. It helps paneer and veggies soft and tender. Now grill it for 17 to 20 minutes at 230 C. Remove the tray from the oven and turn paneer and veggies halfway through grilling.
Every oven is different and so have an eye till the edges of paneer and veggies are charred. Do not grill for a long time as the paneer becomes tough and rubbery. If you have a wooden skewer, arrange paneer and veggies alternately and grill in the oven and enjoy restaurant-style paneer tikka.
Marinate at least for two hours to achieve flavourful tikka. Chop bell pepper and onion to even size to maintain proper cook time. Do not overcook the paneer, else it turns tough.