Cook the pasta according to directions. Before the water starts to boil, add about a tablespoon of salt and olive oil into the water. Stir the pasta to prevent sticking and drain when ready.
In a large saute pan or skillet, heat olive oil and the unsalted butter over medium heat. Once heated, brown the chicken on all sides for 7-10 minutes. Season with salt and pepper and lemon pepper seasoning to taste if using.
Remove the chicken from the pan and set aside. Add the grape tomatoes, cremini mushrooms, and baby spinach leaves. Sauté for 3 minutes until the spinach leaves are cooked. Add the Whole grain Dijon mustard and season with salt and pepper to taste. Stir to combine and reduce to low heat.
Assemble the dressing in a small bowl and combine the Extra Virgin olive oil, lemon juice, garlic powder, chili flakes, and salt and pepper to taste.
Toss the cooked pasta and chicken into the vegetable mixture. Add the dressing and chopped parsley. Combine the pasta mixture until heated through.
Remove the pasta from the heat and add the parmesan cheese before serving. Adjust seasoning with salt and pepper and additional olive oil if needed. Enjoy!