Cook basmati rice and cool completely.
Heat vegetable oil in a pan, crackle mustard seeds and curry leaves.
Add sliced onions and garlic paste, sautéing until light brown.
Add chopped tomatoes, red chili powder, garam masala, and salt; cook until tomatoes turn mushy.
Stir in cooked rice, mix gently on low flame for 3 minutes, and serve warm.