Prep the chicken and aromatics: Pat chicken dry and season with 1/2 teaspoon salt and 1/4 teaspoon pepper. Mince garlic and dice onion.

Sauté in the pressure cooker: Set to Sauté (Normal). Add olive oil. Sear chicken 2–3 minutes, just until lightly golden. Add onion and cook 2 minutes. Stir in garlic for 30 seconds until fragrant. Hit Cancel.

Add cauliflower and broth: Add cauliflower florets and 2 cups of the chicken broth. Scrape up any browned bits on the bottom to avoid a burn warning.

Pressure cook the cauliflower: Seal and cook on High Pressure for 3 minutes. Quick release. Transfer the cauliflower, garlic, onion, and most of the liquid to a blender.

Blend the “Alfredo” sauce: Add Parmesan, butter (if using), yogurt (if using), a pinch of nutmeg, and 1 teaspoon lemon juice. Blend until very smooth and silky. Taste and season with salt and pepper. If too thick, add a splash of broth. Set aside.

Cook the pasta with chicken: Return any remaining liquid to the pot. Add the dry pasta and the remaining 1 cup broth. Stir to distribute. Ensure pasta is mostly submerged (add 1/4 cup water if needed). Seal and cook on High Pressure for 4 minutes (for most short pasta). Quick release and stir.

Combine and finish: Pour the cauliflower Alfredo into the pot with the pasta and chicken. Stir gently over Sauté (Low) for 1–2 minutes until creamy and cohesive. Add more broth or hot water, a few tablespoons at a time, if you prefer a looser sauce.

Brighten and season: Add another squeeze of lemon if needed. Adjust salt, pepper, and red pepper flakes to taste. Turn off Sauté.

Serve: Top with chopped parsley and extra Parmesan. Serve hot.