Mince garlic and cut chicken breast into bite-sized cubes.
Bring a large pot of water to a boil. Salt generously and cook pasta according to package instructions. Reserve about 60ml of cooking water and drain the rest.
While waiting for the pasta to cook, you can cook your chicken. Heat up olive oil in a large nonstick skillet over medium heat. Add chicken, season with salt and pepper, and cook for 4-5 minutes or until cooked through. Remove from skillet.
In the same skillet, add garlic and sauté until fragrant, about 1 minute.
Sprinkle flour over the garlic and stir to combine. Then, slowing pour in chicken stock while stirring constantly to avoid lumps.
Once smooth, add milk and stir. Let simmer for 1 minute or until thickened to desired consistency. If it becomes too thick, thin it out with a splash of pasta cooking water. Season to taste with salt and pepper.
Stir in baby spinach until wilted.
Turn off the heat and stir in cooked pasta and chicken. Divide into serving bowls and top with more black pepper if desired. Enjoy!