Prep the chicken and veggies: Shred or chop the leftover chicken into bite-size pieces.
Halve the tomatoes, mince the garlic, and chop the shallot. Zest the lemon, then cut it and squeeze out 1 to 2 tablespoons of juice.
Warm the pan: Heat a large skillet over medium heat. Add olive oil or butter.
When it shimmers or melts, add the shallot with a pinch of salt. Cook 2–3 minutes until softened.
Add garlic and tomatoes: Stir in garlic and cook 30 seconds, just until fragrant. Add cherry tomatoes and a pinch of red pepper flakes.
Cook 2 minutes until tomatoes start to soften and release juices.
Build the sauce: Pour in chicken broth and bring to a gentle simmer. Stir in cream and lemon zest. Let it bubble for 1–2 minutes to thicken slightly.
Add the chicken: Fold in the leftover chicken.
Warm through for 2–3 minutes. Don’t overcook—just heat it gently to keep it juicy.
Finish with greens and cheese: Add spinach and stir until just wilted, about 1 minute. Turn off the heat.
Stir in Parmesan and 1 tablespoon lemon juice. Taste and adjust with more lemon, salt, and pepper.
Serve your way: Spoon over hot pasta or rice, tuck into a bowl with quinoa, or serve with bread for dipping. Top with chopped parsley or basil.
Optional boost: Drizzle with a little olive oil and add extra Parmesan or a few chili flakes right before serving.