Start by bringing a large pot of salted water to a boil. Add the 3/4 lb penne pasta and cook according to the package instructions until al dente. Drain and set aside.
In a large skillet, heat 1 Tbsp butter and 1 Tbsp olive oil over medium-high heat. Season 1 lb of chicken breast or thighs with salt, pepper, and your favorite seasoning. Add the chicken to the skillet and cook until golden brown and cooked through, about 5-7 minutes. Remove the chicken from the skillet and set aside.
In the same skillet, add 1 1/2 Tbsp unsalted butter and the sliced sweet bell pepper, button mushrooms, and small onion. Season with 1/8 tsp freshly ground black pepper and 1/2 tsp salt. Sauté until the vegetables are tender, about 5 minutes.
Return the cooked chicken to the skillet with the vegetables. Add 1/2 cup sundried tomatoes and stir to combine, cooking for another 2 minutes.
In a medium saucepan, pour in 2 cups heavy whipping cream and bring to a gentle simmer over medium heat. Gradually whisk in 3/4 cup shredded parmesan cheese until melted and smooth. If you like a kick, add 1/2 cup sweet chili sauce at this stage, adjusting to your taste.
Pour the Alfredo sauce over the chicken and vegetable mixture. Add the drained penne pasta and gently toss to coat everything evenly in the creamy sauce. Heat through for 2-3 minutes.
Serve your Chicken and Vegetable Penne Alfredo hot, garnished with additional parmesan cheese if desired. Enjoy this comforting dish with a side salad or your favorite bread.