Preheat oven to 400°F (205°C). Toss tomatoes with olive oil, salt, and black pepper. Roast for 15–18 minutes until blistered. Set aside.
Season chicken breasts on both sides with salt and black pepper.
Heat olive oil in a large skillet over medium heat. Sear chicken for 4–5 minutes per side until golden. Remove and set aside.
In the same skillet, add garlic and cook for 30 seconds until fragrant.
Pour in chicken broth, scraping up browned bits. Stir in heavy cream and bring to a gentle simmer.
Reduce heat to low and add pesto, parmesan cheese, and red pepper flakes if using. Stir until smooth.
Return chicken to the skillet and spoon sauce over the top.
Add roasted tomatoes and simmer for 6–8 minutes until chicken is fully cooked and sauce thickens slightly.
Garnish with fresh basil if desired and serve hot.
