COOK tortellini according to package directions. Drain and set aside.
HEAT a skillet over medium high heat. Add butter. When melted add tortellini in a single layer, making sure it’s sizzling the entire time. Turn occasionally, browning and crisping the pasta. Remove and set aside.
COMBINE red onion, cherry tomatoes and olive oil in a bowl. Season with salt and pepper. Add crispy tortellini and basil and toss. Serve immediately while the tortellini is crispy.
