Prep the chicken: Pat the chicken dry with paper towels.
Season both sides with 1 teaspoon salt, 1/2 teaspoon black pepper, smoked paprika, and Italian seasoning. This helps the chicken brown and stay juicy.
Preheat the skillet: Heat a large skillet over medium-high heat. Add 1 tablespoon oil.
When it shimmers, add the chicken in a single layer. Don’t crowd the pan.
Sear the chicken: Cook 4–6 minutes per side until well browned. If using breasts, aim for a light golden crust.
Transfer chicken to a plate; it will finish cooking later.
Cook the potatoes (or start the veggies): Add another 1/2 tablespoon oil to the skillet. If using potatoes, add them first with a pinch of salt and cook 6–8 minutes, stirring occasionally, until they start to brown. If not using potatoes, skip to the next step.
Add onion and peppers: Stir in sliced onion and bell peppers with another pinch of salt.
Cook 4–5 minutes until softened and lightly caramelized. Scrape up browned bits from the pan as the veggies release moisture.
Add garlic and seasonings: Lower heat to medium. Add minced garlic and red pepper flakes.
Cook 30–45 seconds until fragrant. Do not let the garlic burn.
Deglaze and build the sauce: Pour in chicken broth, Dijon, and honey. Stir to combine, scraping up any remaining browned bits—the flavor lives there.
Simmer 1–2 minutes to slightly thicken.
Return chicken to the pan: Nestle the chicken and any juices back into the skillet. Spoon some sauce over the top. Reduce heat to medium-low, cover, and cook 4–6 minutes, or until the chicken reaches 165°F (74°C) at the thickest part.
Add greens and finish: Stir in spinach or kale and let it wilt, 1–2 minutes.
Add butter if using for a silkier sauce. Finish with lemon zest and a squeeze of lemon juice to brighten the flavors. Taste and adjust salt and pepper.
Garnish and serve: Sprinkle with chopped parsley.
Serve straight from the skillet with crusty bread, rice, or nothing at all—this dish stands on its own.