Begin the pasta by prepping your aromatics - chop the onions and mince the garlic, then set aside.
Put a large pot of SALTED water on the stove on high heat, to start warming up to a boil. The water must be salted - add in 2 tsp - 1 tbsp of salt.
While the water is coming to a boil, add the olive oil to your largest skillet or sauté pan, and bring it medium-low heat. Add in the onion, and sauté for about 2-3 minutes, or until onions are starting to soften. Then, add in the garlic and sauté for another 30 seconds, until fragrant. Turn the heat down to low, if needed, if the garlic starts to brown.
Then, add in all of the salt and dried spices, and sauté with the onions and garlic for another minute or so. Once the spices have "bloomed" and become fragrant, add in the mustard, tomato paste, and butter. Sauté everything together. Once mixed, add in the cream and mix again. Then, reduce heat to low while you wait to add in the pasta (or turn off heat if your stovetop runs hot).
At this point, the salted water in the pot should be boiling. Add in 12 ounces of pasta, and stir. Cook the pasta for 2 minutes LESS than the "al dente" time on the pasta box. Before you take the pasta out, carefully remove about 1 cup of the hot, salted pasta water and set it aside.
Once the pasta has reached 2 minutes less than the "al dente" cooking time, take it out of the pot using a mesh sieve or a slotted spoon, and put it directly into the sauté pan with the cajun cream sauce.
Once all of the pasta is in the saucepan, bring the heat back up to medium low. Stir the pasta all around in the sauce, adding in a little of the reserved pasta water if need be, to loosen.
Continue cooking the pasta in the sauce until it is al dente, continuing to add the reserved pasta water to loosen if necessary. When the pasta is at your desired texture, remove from heat, and stir in the grated cheese until melted.
Top the pasta with the roasted delicata squash, and garnish the pasta with more cheese and fresh parsley, if desired.
Serve, and enjoy!