In a bowl, mix the chicken cubes with 1/2 cup Greek yogurt, 1 tablespoon garam masala, cumin, turmeric, paprika, half the garlic, and half the ginger. Let it sit while you prepare the other ingredients.

Preheat the oven to 425°F. Toss the cauliflower florets with 1 teaspoon olive oil and a pinch of salt. Spread them on a baking sheet and roast for 20 minutes until edges are browned.

While the cauliflower roasts, heat the remaining olive oil in a large skillet over medium heat. Add the diced onion and cook until softened, about 5 minutes.

Stir in the remaining garlic and ginger, then add the marinated chicken. Cook for 6-8 minutes until the chicken is no longer pink on the outside.

Pour in the crushed tomatoes, water, and remaining 1 tablespoon garam masala. Simmer for 10 minutes until the sauce thickens and the chicken is cooked through.

Stir the remaining 1/2 cup Greek yogurt into the sauce and remove from heat. Cook the basmati rice according to package directions.

Serve the chicken tikka masala over the rice and top with the roasted cauliflower and chopped cilantro.