Add the pine nuts, garlic, and lemon juice to the bowl of a food processor and pulse until they are finely chopped.

Next, add the basil leaves and parmesan cheese. Pulse until the basil is finely chopped. 

With the food processor on low speed, slowly drizzle in the olive oil. Pulse until the pesto is smooth and well combined, scraping down the sides of the bowl if needed. 

Set aside until ready to use. 

Cook the cheese tortellini according to the package directions. Cooking times will vary. 

Drain the tortellini and run it under cold water until it is no longer warm to the touch, about 30 seconds. 

Add the tortellini to a large bowl.

Add the pesto and stir gently to coat the pasta with pesto. 

Add the arugula, tomatoes, mozzarella, and pine nuts. Stir to combine and season with salt and pepper to taste. 

Enjoy immediately or store in an airtight container in the fridge for up to three days. I prefer to enjoy this pasta salad at room temperature but it can be enjoyed cold as well.