Place plastic wrap over each chicken breast and pound to about ½-inch thickness. Pat dry.
Combine dredge ingredients and coat the chicken evenly, shaking off excess.
Heat butter and olive oil in a skillet over medium-high heat.
Add chicken and cook for 4–5 minutes per side until golden. Remove and set aside.
Turn off heat, add chicken broth, then return heat to medium. Scrape the skillet to deglaze. Let it reduce by half (6–7 minutes). Add garlic in the last minute.
Warm the half and half slightly, then add gradually while stirring. Let it gently simmer.
Stir in cream cheese until smooth.
Add spinach and cook until wilted. Add lemon juice if desired.
Return chicken to the skillet and simmer until heated through.
Garnish with parsley and serve your creamy Chicken Florentine.