Something I think is so great about cacio e pepe recipes is the fact that one of the main ingredients is pasta water. It’s an essential component to the flavour and texture of the pasta and finishes off the whole cooking process so beautifully. Also it’s free and it’s right there. You’re already cooking the pasta in water, all you have to do is save it when you’re done cooking the pasta.
According to this recipe that I use often: https://www.epicurious.com/recipes/food/views/cacio-e-pepe-365162, the pasta water is brought to a simmer near the end and you add the pasta and cheese to it immediately afterwards. It sounds gross and counterintuitive to just add a bunch of starchy water to a skillet and throw some cooked pasta and cheese in there and hope for the best but this recipe kills it every time. I’ve never messed it up. I don’t always have the right breakdown of pecorino to parmesan. But I always have butter, cheese and pepper in my house which are basically the only other ingredients. It’s mac and cheese for grown ups. It’s fancy and impressive while not expecting too much of you and I love it for that.