Pat the chicken thighs dry with paper towels. Season both sides evenly with salt, black pepper, paprika, and garlic powder. Let them sit for 10 minutes to absorb the seasoning.
Heat olive oil in a large, heavy-bottomed pan over medium-high heat. Once hot, add the chicken in a single layer. Sear for 4–5 minutes per side until golden brown. The chicken does not need to be fully cooked at this stage. Remove and set aside.
In the same pan, reduce heat to medium and add butter. Once melted, stir in the minced garlic and sauté for about 30 seconds until fragrant, being careful not to burn it.
Add the chopped roasted red peppers and cook for 2–3 minutes, allowing them to release their smoky sweetness into the pan.
Pour in the chicken broth and gently scrape up any browned bits from the bottom of the pan. Let it simmer for 2 minutes to build flavor.
Lower the heat and add the heavy cream, stirring continuously to combine. Allow the sauce to gently simmer for 3–4 minutes until it begins to thicken slightly.
Stir in the grated parmesan cheese gradually, mixing until fully melted and the sauce becomes smooth and creamy.
Add oregano and chili flakes, then taste and adjust seasoning if needed.
Return the seared chicken to the pan, nestling it into the sauce. Cover and let it cook on low heat for 10–12 minutes, or until the chicken is fully cooked and tender.
Add the spinach leaves and stir gently until wilted into the sauce.
Simmer uncovered for another 2–3 minutes to achieve the desired sauce consistency.
Garnish with fresh parsley and serve warm.