Slice the chicken breasts in half lengthwise to create thinner cutlets. Season lightly with salt and pepper.
Heat olive oil in a large skillet over medium-high heat.
Sear the chicken for 1–2 minutes per side until lightly golden. Remove and set aside.
Add butter, shallot, garlic, and red pepper flakes to the skillet. Cook for about 5 minutes until softened and fragrant.
Stir in the sundried tomatoes and orzo. Toast for 1–2 minutes, stirring frequently.
Add the cooking wine or extra broth and scrape up any browned bits from the bottom of the pan.
Stir in Dijon mustard, thyme, and vegetable stock. Bring to a gentle boil.
Return the chicken to the pan.
Reduce heat, cover, and simmer for 10–15 minutes, stirring occasionally, until the orzo is tender and most of the liquid is absorbed.
Remove the chicken and slice into strips.
Stir the heavy cream, Parmesan cheese, spinach, basil, and lemon juice into the orzo mixture.
Taste and adjust seasoning with salt and pepper as needed.
Return the sliced chicken to the skillet.
Garnish with additional basil and serve warm.