Preheat oven to 400°F (200°C). Add sliced onions to a baking dish. Toss with paprika, garlic powder, salt, pepper, Italian seasoning, and 4 tbsp olive oil until well coated.
Slice the top off the garlic head (about ¼ inch), drizzle with 1 tbsp olive oil, sprinkle with salt, and place it cut-side up on top of the onions.
Cover with foil and bake for 1 hour, tossing the onions every 20 minutes (twice total). Each time, add a splash of water to prevent burning. You're looking for deep golden, jammy onions.
While that magic is happening, cook pasta according to package instructions. Reserve up to 1 cup of pasta water before draining.
Remove garlic from the dish and let cool slightly. Squeeze the roasted garlic into the onions.
Add chili crisp, cream (or coconut milk), soy sauce, lemon juice, Parmesan, and cooked pasta. Toss everything together, adding some pasta water as needed until glossy and saucy. Taste and adjust salt if needed.
Finish with extra Parmesan, chili crisp, and fresh parsley if desired.
