Marinate the chicken (10–15 minutes): In a bowl, combine the chicken, yogurt or lemon juice, 1/2 teaspoon garam masala, 1/2 teaspoon cumin, a pinch of salt, and pepper.
Toss and let it sit while you prep the sauce. Even a short marinade makes a difference.
Cook the pasta: Bring a large pot of salted water to a boil. Cook the penne until just shy of al dente according to package directions.
Reserve 1/2 cup pasta water, then drain.
Brown the chicken: Heat 1 tablespoon oil and 1 tablespoon butter in a large skillet over medium-high. Add the chicken in a single layer. Sear until lightly browned and mostly cooked through, about 4–6 minutes.
Transfer to a plate; it will finish in the sauce.
Sauté aromatics: In the same pan, add another tablespoon of oil if needed. Lower to medium. Add the onion with a pinch of salt and cook until soft and golden, 5–7 minutes.
Stir in garlic and ginger; cook 30–60 seconds until fragrant.
Toast the spices: Add remaining garam masala, cumin, coriander, turmeric, paprika, and cayenne (if using). Stir for 30 seconds to bloom the spices. If the pan is dry, add a splash of oil to prevent burning.
Build the sauce: Pour in crushed tomatoes and the sugar or honey.
Simmer 5–7 minutes, stirring occasionally, until slightly thickened and the sharpness mellows.
Add cream and butter: Reduce heat to low. Stir in 1/2 cup of the cream and 1–2 tablespoons butter until silky. Add a splash of broth or pasta water if the sauce is too thick.
Taste and adjust salt.
Finish the chicken: Return the chicken and its juices to the pan. Simmer 3–4 minutes until cooked through and tender. The sauce should be rich but scoopable; thin with a little pasta water as needed.
Toss with penne: Add the drained penne directly to the skillet.
Toss over low heat until every piece is coated. Stir in the remaining cream if you want extra richness, and a handful of chopped cilantro if you like freshness.
Serve: Finish with a small knob of butter for gloss, cracked black pepper, and a squeeze of lemon to brighten. Plate and garnish with more cilantro.