Make the Chili Oil: Combine chili flakes, sesame seeds, garlic, ginger, sugar, salt, and a cinnamon stick in a heat-safe bowl. Heat the neutral oil in a small pan until hot (test by adding a small piece of garlic—if it sizzles, it's ready). Carefully pour the hot oil over the chili mixture and stir. Set aside to infuse. Skip this step if you already have chili oil on hand!
Bring a pot of water to a boil, salt it generously, and cook your pasta until just al dente—it’ll finish cooking in the sauce. Before draining, reserve ½ cup of the starchy pasta water.
While the pasta cooks, sauté half an onion in a bit of oil until softened.
Stir in the tomato paste. Let it cook down for about 5 minutes, stirring occasionally, until it deepens in colour and looks a bit caramelized.
Pour in the vodka to deglaze the pan, letting it reduce for a minute or two to cook off the alcohol.
Add a drizzle (or more) of chili oil, depending on your spice preference, and stir to combine.
Stir in the heavy cream and cook until it lightly bubbles.
Add the cooked pasta and reserved pasta water to the sauce. Stir everything together until glossy and fully coated.
Serve it up with another drizzle of chili oil and some freshly grated parmesan!