Part 1: Roasting the Spaghetti Squash

1. Preheat and Prep: Preheat your oven to 400°F (200°C). Line a large baking sheet with parchment paper for easy cleanup.
2. Cut the Squash: This is often the hardest part! Place the spaghetti squash on a stable cutting board. Using a large, sharp chef’s knife, carefully slice the squash in half lengthwise from stem to end. If it’s very tough, you can microwave the whole squash for 3-5 minutes to soften the skin slightly before cutting.
3. Scoop the Seeds: Use a spoon to scoop out the seeds and stringy pulp from the center of each half, just as you would with a pumpkin. Discard the seeds or save them for roasting later.
4. Season and Roast: Drizzle the cut sides of the squash with 1 tablespoon of olive oil. Use your hands to rub it all over the inside flesh. Season generously with salt and pepper. Place the squash halves cut-side down on the prepared baking sheet.
5. Bake to Perfection: Roast in the preheated oven for 40-50 minutes. The cooking time will vary depending on the size of your squash. It’s done when the outside is firm enough to hold its shape, but the inside is tender enough to be easily pierced with a fork. You should be able to easily shred the flesh into spaghetti-like strands.

Part 2: Marinating and Cooking the Chicken

1. Marinate the Chicken: While the squash is roasting, prepare the chicken. In a medium-sized bowl, combine all the marinade ingredients: Greek yogurt, lemon juice, minced garlic, grated ginger, garam masala, turmeric, cumin, Kashmiri red chili powder, and salt. Add the cubed chicken thighs and mix thoroughly until every piece is coated.
2. Let it Rest: Cover the bowl and let the chicken marinate for at least 30 minutes at room temperature. For even more tender and flavorful chicken, you can marinate it in the refrigerator for up to 8 hours. The yogurt and lemon juice act as a powerful tenderizer.
3. Cook the Chicken: In a large, heavy-bottomed pot or Dutch oven, heat 1 tablespoon of olive oil and 1 tablespoon of the butter over medium-high heat. Once the butter is melted and sizzling, add the marinated chicken to the pot in a single layer. You may need to do this in two batches to avoid overcrowding the pan.
4. Get a Good Sear: Cook the chicken for 3-4 minutes per side, until it’s nicely browned and develops a slight char. This searing process, known as the Maillard reaction, builds a tremendous amount of flavor. The chicken doesn’t need to be cooked all the way through at this stage. Once browned, remove the chicken from the pot with a slotted spoon and set it aside on a plate.

Part 3: Creating the Velvety Butter Chicken Sauce

1. Sauté Aromatics: Reduce the heat to medium. Add the remaining 2 tablespoons of butter to the same pot. Once melted, add the finely chopped onion and sauté for 5-7 minutes, until soft and translucent, scraping up any browned bits (fond) from the bottom of the pot.
2. Bloom the Spices: Add the minced garlic and grated ginger to the pot and cook for another minute until fragrant. Be careful not to burn them. Now, add the dry spices for the sauce: ground coriander, cumin, garam masala, turmeric, and Kashmiri red chili powder. Stir constantly for about 30-60 seconds. This step, known as blooming, toasts the spices in fat, which deepens and intensifies their flavor.
3. Build the Sauce Base: Pour in the can of crushed tomatoes. Stir everything together, ensuring the spices are well incorporated. Bring the sauce to a gentle simmer.
4. Simmer and Deepen Flavor: Reduce the heat to low, cover the pot, and let the sauce simmer for at least 15-20 minutes. This allows the flavors to meld and the acidity of the tomatoes to mellow out. The sauce will thicken and darken slightly.
5. Blend for Smoothness (Optional but Recommended): For a truly authentic, silky-smooth butter chicken sauce, this step is key. Carefully transfer the hot tomato sauce to a high-speed blender. You can also use an immersion blender directly in the pot. Blend until the sauce is completely smooth and velvety. Return the blended sauce to the pot.
6. Finish the Sauce: Stir in the heavy cream. Let the sauce gently heat through, but do not let it come to a rapid boil after adding the cream. Add the crushed dried fenugreek leaves (Kasuri Methi)—this is a secret ingredient that gives butter chicken its signature aroma.
7. Final Touches: Add the seared chicken and any accumulated juices back into the pot with the sauce. Stir to coat. Let it simmer gently for another 5-10 minutes, or until the chicken is cooked through and tender. Now, taste the sauce. Add salt as needed. If the sauce tastes a bit too acidic from the tomatoes, stir in 1-2 teaspoons of sugar (or a low-carb sweetener) to balance the flavors.

Part 4: Assembling the Dish

1. Shred the Squash: Once the spaghetti squash is cooked and cool enough to handle, use a fork to scrape and fluff the flesh from the skin. The strands will separate easily, resembling spaghetti.
2. Serve: Create a bed of the spaghetti squash strands on each plate or in a shallow bowl. Generously spoon the hot butter chicken and its luxurious sauce over the top. Garnish with a sprinkle of fresh chopped cilantro and an optional drizzle of extra cream or a dollop of yogurt.