Select saute on the pressure cooker and add butter. When melted, add garlic cloves and saute until fragrant, about 2 minutes, stirring constantly so the garlic doesn’t burn. Add cauliflower, broth, and salt. Secure the lid and turn pressure release knob to a sealed position. Cook at high pressure for 6 minutes.
While the cauliflower is cooking, heat a pot of water to boiling on the stove top. Add pasta and cook until al dente. Reserve about 1 cup of water and then drain the pasta. Return pasta to the empty pot.
When pressure cooking is complete, use a natural release for 10 minutes and then release any remaining pressure.
Blend with an immersion blender right in the pot until very smooth or carefully transfer to a blender and puree, until smooth. By hand, stir in the chopped spinach and green onions and allow the hot sauce to wilt the spinach.
Pour sauce over the pasta and toss. Add a half cup or so of the reserved pasta water to the pasta if needed. The starchy water will help the sauce to stick to the pasta.
Serve hot with a garnish of crumbled gorgonzola cheese, sun-dried tomatoes, and a drizzle of balsamic vinegar.
The sauce heats back up very nicely so you could also make the sauce in advance and have it ready to pour over pasta for a quick, healthy, delicious meal any night of the week. Also amazing over rice, as a sauce on pizza, or a dip for bread and roasted veggies. It does it all!