Stir together ingredients for bruschetta in a bowl then set aside. Can be made a day ahead of time.
Bring a large pot of water to a boil then salt heavily and add spaghetti. Cook until al dente then drain and set aside.
Meanwhile, heat a large skillet over medium-high heat then mist or spray with extra virgin olive oil or nonstick spray. Season chicken on both sides with Italian seasoning, garlic salt, and pepper then saute for 2-3 minutes a side or until cooked through. Remove to a plate then set aside. Turn heat down to medium then remove skillet from heat to cool slightly.
Return skillet to heat then add bruschetta mixture and simmer for 2-3 minutes or until tomatoes are heated through and juices are slightly thickened. Add pasta and parmesan cheese then toss to combine. Taste then add salt if necessary. Scoop into bowls then top with more parmesan cheese, balsamic reduction if using, and chicken, then serve.
Simmering the chopped Roma tomatoes with balsamic vinegar requires precise timing; cooking the mixture for precisely two to three minutes breaks down cell walls just enough to release internal pectin without entirely dissolving the structural integrity of the fruit. Acid from the vinegar reacts chemically with the natural sugars in the tomatoes, concentrating umami compounds while the olive oil emulsions form a cohesive sauce. Microplaning the garlic yields a finer paste than mincing, distributing allicin compounds uniformly across the pan rather than leaving pungent pockets. Sautéing the chicken cutlets over medium-high heat for two to three minutes per side creates a Maillard reaction on the surface proteins while retaining interior moisture. Gluten-free spaghetti demands aggressive water salting because starch molecules hydrate differently than wheat pasta, absorbing ambient sodium more slowly. Parmesan cheese introduces glutamates that bridge the sharp acidity of the tomatoes and the savory notes of the seared poultry. Dietary modifications require careful attention to binding agents, though naturally gluten-free grain varieties substitute seamlessly into boiling water without structural compromise. Resting the tomato mixture up to twenty-four hours ahead allows ambient osmosis to draw excess water out, concentrating flavors before the hot pan reduces the liquid further.