Mix yogurt with 1 teaspoon paprika powder in a bowl. Peel and chop onion, crush 2 garlic cloves, and add to yogurt. Season with salt. Wash ½ bunch parsley, chop finely, and stir in. Place chicken breasts in the bowl so they're completely covered by marinade. Cover and refrigerate overnight (minimum 8 hours).
Pat chicken breasts dry with kitchen paper. Heat a large heavy pan (preferably cast iron) to medium-high heat. Sear chicken skin-side down for 3 minutes. Flip and sear other side for 2 minutes. Reduce heat to medium-low, add remaining marinade, and simmer for 5–6 minutes, or until internal temperature reaches 74°C (165°F). Remove chicken and let cool.
In the same pan, heat 20 g butter over medium heat. Deglaze with 125 ml white wine, stirring and scraping up browned bits for 1–2 minutes. Crumble 80 g Gorgonzola and stir until melted, about 1–2 minutes. Fold in 125 ml cold defatted chicken broth. The sauce should be frothy.