Bake Hubbard squash in the oven: Place half a squash – seeds and fibers removed – on a baking tray, cut-side down. Add 1/4 cup water to the tray. Bake in a 350° degree oven for about 45 to 60 minutes until well cooked. Remove and allow to cool, then scoop out cooked flesh. You'll need about 4 cups for this recipe.
In a large sauté pan, heat vegetable oil (canola, grape seed, sunflower) along with fenugreek seeds and cumin seeds over high heat. Add sliced red onions, and sauté till golden; add minced garlic and serrano chili to the pan and stir for a few seconds.
Add turmeric, amchoor and red chili powder to the pan and toast the spices for a minute or so. (If you don't have amchoor, you can stir in 1 tablespoon freshly squeezed lemon juice over the dish just before taking it off the heat.)
Add the squash and kosher salt, stirring it and incorporating the masala. When squash is heated through, check for salt and serve, garnished if you'd like with some chopped cilantro leaves.