Saute the aromatics: Heat the olive oil in a large pot over medium heat. Add the finely chopped onion, minced garlic, and sliced leek. Sauté for about 5 minutes, stirring occasionally, until the vegetables are softened and fragrant.
Add the veggies: Add the grated carrot and grated potato to the pot. Stir well to combine with the other vegetables and cook for an additional 2-3 minutes. The grated vegetables will help create a creamy texture in the soup.
Add the chicken: Add the diced chicken breast to the pot. Cook for 5-7 minutes, stirring occasionally, until the chicken is lightly browned on the outside. It doesn't need to be fully cooked at this point.
Add the broth: Pour in the chicken broth and bring the mixture to a boil. Once boiling, reduce the heat to low and let it simmer for 10 minutes. This will allow the flavors to meld and the chicken to cook through.
Add the pasta: Add the sliced carrot rounds and the uncooked pasta to the pot. Stir well and let the soup simmer for another 8-10 minutes, or until the pasta is al dente and the carrots are tender.
Make a slurry: In a separate bowl, whisk together the skim milk and cornstarch until smooth. This will thicken the soup without adding extra fat.
Thicken the soup: Slowly pour the milk and cornstarch mixture into the pot with the corn kernels and peas, stirring constantly to prevent lumps from forming. Increase the heat to medium and cook for an additional 3-5 minutes, or until the soup has thickened to your desired consistency.
Taste and adjust: Taste the soup and adjust the seasoning with salt and pepper as needed. Remember that the chicken broth may already contain some salt, so add gradually to avoid over-salting.
Let it stand: Remove the pot from the heat and let it stand for 5 minutes before serving.
Garnish and serve: Ladle the creamy pasta chicken soup into bowls and serve hot. You can garnish with fresh herbs like parsley or a sprinkle of grated Parmesan cheese if desired.