Season the chicken thighs with salt and black pepper.
Heat olive oil and butter in a large skillet over medium-high heat.
Add chicken thighs and pan-sear until golden brown on both sides, about 5-6 minutes per side. Remove chicken and set aside.
In the same skillet, add minced garlic and sauté until fragrant, about 1 minute.
Add chopped sun-dried tomatoes and cook for 2 minutes.
Pour in chicken broth and simmer for 3 minutes to reduce slightly.
Lower heat to medium and stir in heavy cream, parmesan cheese, and red pepper flakes.
Return chicken thighs to the skillet and simmer in the sauce for 10 minutes, until chicken is cooked through and sauce thickens.
Adjust seasoning with salt and black pepper as needed.
Plate chicken thighs arranged on a shallow white plate, spoon sauce generously over and around, and garnish with fresh basil leaves.