Slice each chicken breast in half lengthwise to create thinner cutlets. Gently pound the pieces to an even thickness for consistent cooking.
Season both sides of the chicken with salt and black pepper.
Melt 2 tablespoons of butter in a large skillet over medium to medium-high heat. Add the chicken and sear for about 4–5 minutes per side, or until golden and cooked through. Chicken should reach an internal temperature of 165°F (74°C). Transfer to a plate.
Reduce the heat slightly and add the remaining tablespoon of butter to the same skillet. Add the onion, garlic, roasted red peppers, paprika, crushed red pepper flakes, salt, and black pepper.
Sauté for about 4–5 minutes, stirring occasionally, until the onion has softened and the garlic is fragrant.
Pour in the chicken stock and scrape the bottom of the skillet to release the flavorful browned bits. Bring to a gentle simmer and cook until the liquid has reduced by roughly half.
Reduce the heat to medium-low and slowly stir in the heavy cream. Simmer gently until the sauce begins to thicken.
Add the freshly grated Parmesan and stir until completely melted and the sauce is smooth.
Stir in the fresh basil and cook for another 1–2 minutes, just until the leaves soften.
Return the chicken and any accumulated juices to the skillet. Spoon the sauce over the chicken and gently warm everything together for 1–2 minutes.
Serve the Creamy Parmesan Basil Chicken recipe warm with extra basil and Parmesan if desired.