Boil the Tortellini by filling a large pot with water, adding a pinch of salt, bringing it to a boil, adding the tortellini, and cooking for about 3-5 minutes until they float. Drain and set aside.

Prepare the Sauce Base by melting butter in a skillet over medium heat, adding flour to create a roux, and stirring for about 1 minute until smooth.

Add Chicken Broth and Lemon by pouring in chicken broth and lemon juice, whisking to prevent lumps, and letting it simmer for about 2-3 minutes until slightly thickened.

Incorporate Cream and Garlic Powder by stirring in heavy cream and garlic powder, whisking for another 2-3 minutes until thickened to a velvety consistency.

Mix in Parmesan Cheese by removing the skillet from heat, adding in Parmesan cheese, and stirring until melted and fully incorporated.

Combine Everything Together by gently folding in the drained tortellini and shredded cooked chicken, tossing together over low heat for 1-2 minutes until heated through.

Final Seasoning by tasting and adjusting with salt and pepper; serve immediately, garnished with extra Parmesan cheese or herbs.