In a large skillet, heat olive oil and butter over medium-high heat. Season chicken breasts with salt and pepper, then add to the skillet. Cook for 4-5 minutes on each side until golden and cooked through. Remove the chicken and set aside.

In the same skillet, add diced onion and sauté on medium heat for about 5 minutes until translucent. Stir in minced garlic and sauté for another 30 seconds until fragrant.

Add long-grain white rice to the skillet with the onions and garlic, stirring well. Toast the rice for 1-2 minutes, allowing it to lightly brown.

Slowly pour in the chicken broth while scraping the browned bits from the bottom. Bring to a gentle boil, then return the chicken to the pan. Cover and let simmer for 18-20 minutes until the rice has absorbed the broth.

After the rice is cooked, stir in heavy cream until incorporated. Cook uncovered for another 2-3 minutes, seasoning with salt and pepper, then garnish with parsley before serving.