Step 1

Roughly chop your pistachios into small bits. To the base of your food processor, add the chopped pistachios, basil leaves, garlic cloves, parmesan, and some salt and pepper. Mix until combined.

Step 2

Slowly pour the olive oil into the food processor while it's on, stopping to scrape down the sides. Keep going until you get a pesto-like consistency.

Step 3

Cook your pasta according to package directions in a large pot of salted water. Before draining the pasta, reserve about ½ cup of the pasta water. Set aside.

Step 4

In a large pan on medium heat, melt the butter. Add the diced onions and cook for 3-5 minutes, or until tender and fragrant.

Step 5

Add the pistachio pesto to the pan and turn the heat to medium-low. Stir well, cooking for two minutes.

Step 6

Slowly add the cream to the pan, mixing constantly. Once all of the cream is added and the sauce is mixed and well-incorporated, add the cooked pasta to the pan. Toss to coat.

Step 7

Add the other ⅔ cup of parmesan to the pasta. Stir, and add a few tablespoons (or more) of reserved pasta water until you get the consistency you want.Add salt and pepper, and taste test to adjust seasonings accordingly. Serve with the extra chopped pistachios and more parmesan on top.