This one pot meal is full of flavor and color, and you'll love this Cajun take on pasta (our paleo members will be enjoying this as a saute with broccoli). Smarts: If you ever have sour cream around, add a few dollops to a grain dish to give it some texture and flavor.
Bring a saucepan of water to boil. Salt generously and add pasta. Cook until al dente, tender but not soggy. Keep ~1 cup (236 ml) of pasta water (this amount is for 4 servings - adjust accordingly).
Heat a saute pan over medium-high heat. Add cooking oil and then chicken to the heated oil. Saute for 4 to 6 minutes, until you get some color and some yummy chicken juices running out. Remove from pan and set aside.
Return saute pan to medium-high heat and now add ½ the pasta water to the pan scraping up any brown bits that may have formed. Add onions and white parts of green onions to the pan and saute for ~3 minutes, until softened. Next add in bell peppers, mushrooms, diced tomatoes and remainder of the pasta water. Saute for 5 to 6 minutes, until peppers have softened but still slightly crunchy.
Return chicken to pan. Mix in pasta, second part of Cajun seasoning, and sour cream. Toss until everything is mixed through. Take off heat and finish with green parts of green onions and lemon juice. Season to taste with more Cajun seasoning and salt and pepper.