Roast the tomatoes – Slice the cherry tomatoes into halves, spray with cooking spray, and season with salt and pepper. Roast the tomatoes either by air frying (10 minutes) or adding to the oven for 400 degrees (20 minutes).
Marinade the chicken – Add the salt, pepper, paprika, and oregano into a mixing bowl and mix. Cut the chicken into small bite-sized pieces, trimming off the excess fat. Mix the chicken pieces thoroughly with the spice mix so that each piece is coated with the mixture.
Cook the pasta – Prepare the pasta according to the package directions. Be sure to boil in salted water and save some of the pasta water.
Prepare the vegetables – Mince the onions and garlic and watch the spinach thoroughly.
Cook the chicken – Heat a skillet over medium-high heat. Spray with cooking spray and add the chicken pieces in a single layer, cooking for about 3-4 minutes on each side, or until fully cooked.
Sauté the aromatics – Add the onions, garlic, tomato paste, and Calabrian chili if using into the pan and sauté for about 1-2 minutes, or until golden.
Add the spinach and milk – Lower the heat down to medium-low and add in the milk and cornstarch along with the spinach. Mix everything thoroughly, adding pasta water as needed to achieve the desired sauce consistency.
Mix in the pasta – Mix in the pasta along with 2 teaspoon of parmesan cheese and continue to use pasta water to achieve the desired sauce consistency.
Garnish and serve – Plate the pasta, garnishing with parmesan cheese and red pepper flakes if desired.