Easy Chicken Seekh Kebab

Name: Easy Chicken Seekh Kebab
Ingredients: 1 lb ground chicken, use thigh pieces with fat; 1 small onion; 4 cloves garlic; 1 inch ginger; 1 finely chopped green chili, optional; 1/4-1/2 cup chopped cilantro (may add some mint too); 1 teaspoon salt; 2 teaspoon cumin powder (toast seeds and grind them if possible); 2 teaspoon coriander powder (toast seeds and grind them if possible); 1/2 teaspoon black peppercorn (toast seeds and grind them if possible); 1 teaspoon garam masala; 3 tablespoon melted butter; 2-3 tablespoon neutral cooking oil