Cook the pasta: Bring a large pot of salted water to a boil. Cook pasta until al dente. Reserve 1/2 cup pasta water, then drain.

Mix the Cajun rub: If using store-bought, taste it first. For homemade, combine 2 teaspoons smoked paprika, 1 teaspoon garlic powder, 1 teaspoon onion powder, 1/2 teaspoon dried oregano, 1/2 teaspoon dried thyme, 1/2 teaspoon cayenne (to taste), 1/2 teaspoon black pepper, and 3/4 teaspoon salt.

Season the chicken: Pat dry and slice into thin strips. Toss with 1 tablespoon olive oil and 1–1.5 tablespoons Cajun seasoning to coat.

Sear the chicken: Heat a large skillet over medium-high. Add chicken in a single layer. Cook 4–6 minutes, turning once, until browned and cooked through. Remove to a plate.

Sauté the veggies: In the same skillet, add another drizzle of oil if needed. Add sliced onion and bell peppers with a pinch of salt. Cook 4–5 minutes until softened and lightly charred. Add minced garlic and cook 30 seconds.

Build the lighter sauce: Reduce heat to medium-low. Add chicken broth and scrape up browned bits. Stir in milk and 1–2 teaspoons Cajun seasoning. Simmer 2 minutes to warm through.

Thicken gently: If you want a silkier sauce, whisk 1 teaspoon cornstarch with 1 tablespoon water and stir into the skillet. Simmer 1 minute until slightly thickened.

Finish creamy (off heat): Turn off the heat. Stir in Greek yogurt and Parmesan until smooth. Add a squeeze of lemon for brightness. Taste and adjust salt, pepper, or Cajun heat.

Combine: Add cooked pasta, spinach, and the chicken (plus any juices) to the skillet. Toss until spinach wilts and everything is coated. Use a splash of reserved pasta water if the sauce seems too thick.

Garnish and serve: Top with chopped parsley or green onions and extra Parmesan if you like. Serve hot with lemon wedges.