Prep the chicken: Pat chicken dry. If breasts are thick, slice horizontally into cutlets for even cooking.
Season both sides with salt, pepper, Italian seasoning, and smoked paprika.
Sear the chicken: Heat olive oil in a large skillet over medium-high. Add chicken and sear 3–4 minutes per side until golden and just cooked through (internal temp 165°F). Transfer to a plate and tent with foil.
Sauté aromatics: Reduce heat to medium.
In the same pan, add garlic and sun-dried tomatoes. Cook 30–60 seconds until fragrant, stirring so the garlic doesn’t brown.
Deglaze: Whisk the cornstarch into the chicken broth (if using), then pour into the pan. Scrape up browned bits.
Let it simmer 1–2 minutes to slightly reduce.
Make it creamy: Lower heat to medium-low. Stir in milk and parmesan until smooth. Remove the pan from heat and whisk in Greek yogurt until the sauce turns silky.
Return to low heat only if needed to warm; do not boil.
Add greens: Stir in spinach until just wilted. Add a pinch of salt, black pepper, and red pepper flakes if you like heat.
Finish and balance: Return chicken and any juices to the pan. Spoon sauce over the chicken and simmer on low 1–2 minutes.
Stir in lemon juice. Taste and adjust seasoning.
Serve or meal prep: Garnish with fresh basil or parsley. Plate with your chosen sides, or divide into meal prep containers with extra sauce spooned over the top.