Prep the chicken. Pat the chicken dry.
Season on both sides with salt, pepper, and garlic powder. Thin cutlets cook faster and stay tender, so slice thicker breasts in half horizontally if needed.
Crisp the bacon. Place bacon in a large, cold skillet. Turn heat to medium and cook, stirring, until crisp, about 6–8 minutes.
Transfer bacon to a plate and leave about 2 tablespoons of bacon fat in the pan.
Sear the chicken. Add olive oil if the pan looks dry. Sear chicken over medium-high heat until golden and cooked through, about 3–4 minutes per side for cutlets. Transfer to a plate and tent with foil.
Build the flavor base. Lower heat to medium.
Add minced garlic and stir 30 seconds until fragrant. Sprinkle in the flour and whisk to form a paste. Cook 1 minute to remove the raw flour taste.
Make the sauce. Slowly whisk in chicken broth, scraping up browned bits.
Add heavy cream, ranch seasoning, and Dijon. Simmer gently for 3–4 minutes until slightly thickened.
Finish the sauce. Stir in lemon juice to brighten. If using, melt in Parmesan until smooth.
Taste and adjust salt and pepper. Remember, the bacon adds saltiness.
Add greens and bacon. Fold in spinach until just wilted, 30–60 seconds. Return bacon to the skillet, reserving a little for garnish if you like.
Bring it together. Nestle chicken back into the sauce with any juices from the plate.
Simmer 1–2 minutes so everything warms through and the flavors mingle.
Serve. Top with chopped chives or parsley and the reserved bacon. Serve over rice, buttered noodles, mashed potatoes, cauliflower mash, or with crusty bread to catch the sauce.