Heat grapeseed oil in a skillet over medium heat; cook and stir onion and garlic until tender, about 5 minutes. Stir in rice, curry powder, garam masala, and cumin seeds. Continue to cook and stir until rice is toasted, 1 to 2 minutes more.
Pour broth into rice mixture and season with salt; bring to a boil. Reduce heat to low, cover, and cook until rice is tender and liquid is absorbed, 45 to 50 minutes.
