Chicken tikka refers to chunks of boneless chicken that have been marinated in a mixture of yogurt and spices, then cooked.

Here is a recipe for making classic chicken tikka masala:

Ingredients:

• 1 lb boneless, skinless chicken breasts, cut into 1-inch cubes
• 1 cup plain yogurt
• 2 tablespoons lemon juice
• 2 cloves garlic, minced
• 1 tablespoon grated ginger
• 1 teaspoon garam masala
• 1 teaspoon paprika
• 1/2 teaspoon cayenne pepper
• 1 teaspoon salt
• 2 tablespoons olive oil or butter
• 1 onion, diced
• 3 cloves garlic, minced
• 1 tablespoon grated ginger
• 1 teaspoon garam masala
• 1 teaspoon paprika
• 1 teaspoon cumin
• 1 teaspoon salt
• 1 (14 oz) can diced tomatoes
• 1 cup chicken broth or water
• 1 cup heavy cream
• Chopped cilantro for garnish

Instructions:

1. Marinate the chicken: In a bowl, mix the chicken with yogurt, lemon juice, 2 cloves garlic, 1 tbsp ginger, 1 tsp garam masala, paprika, cayenne and 1 tsp salt. Cover and marinate for 30 mins to an hour.
2. Make the sauce: Heat oil/butter in a skillet over medium-high heat. Add the onions and sauté for 2-3 minutes until translucent. Add the 3 cloves garlic and 1 tbsp ginger and cook for 1 minute until fragrant.
3. Stir in the 1 tsp each of garam masala, paprika, cumin and 1 tsp salt. Cook for 1-2 minutes to toast the spices.
4. Pour in the diced tomatoes with juices and the chicken broth. Bring to a simmer and cook for 10-12 minutes to thicken slightly.
5. Remove chicken from marinade and cook in a skillet or grill for 2-3 minutes per side until starting to char.
6. Add the grilled chicken chunks to the simmering sauce along with the heavy cream. Stir to combine and cook for 5 more minutes.
7. Taste and adjust seasoning as needed, adding more salt if desired.
8. Garnish with chopped cilantro and serve over basmati rice or with naan bread.

The key steps are marinating the chicken to infuse flavors, grilling it briefly before adding to the creamy tomato sauce. The sauce gets its richness from cream and a mix of aromatic spices. Adjust spice levels to your taste preference. Enjoy this classic Indian restaurant dish at home!