In a large skillet, heat olive oil over medium-high heat. Season chicken breasts with salt, pepper, and oregano. Sear chicken for 5-7 minutes per side until golden and reaches 165°F. Remove chicken and set aside.

In the same skillet, add more olive oil if needed and sauté sliced mushrooms for 4-5 minutes until soft and golden brown.

Add minced garlic to mushrooms and sauté for about 1 minute until fragrant. Then, add cherry tomatoes, capers, and spinach. Cook for 2-3 minutes until spinach wilts and tomatoes soften.

Pour in heavy cream and chicken broth, stirring well. Increase heat and bring to a gentle simmer, allowing sauce to thicken.

After simmering, stir in grated Parmesan cheese until melted and smooth.

Return chicken to the skillet, letting it warm through for 2 minutes.

Plate the dish, garnish with parsley and red pepper flakes if desired.