Mix the Cajun seasoning. In a small bowl, combine smoked paprika, cayenne, thyme, oregano, onion powder, black pepper, and salt. Taste a pinch and adjust cayenne and salt as needed.
Season the chicken. Pat chicken thighs dry. Toss with 1 tablespoon oil and about two-thirds of the Cajun seasoning until evenly coated.
Cook the broccoli. Heat 1 tablespoon oil in a large skillet over medium-high heat.
Add broccoli and a pinch of salt. Sauté 3–5 minutes until bright green with some char. Add 2 tablespoons water, cover, and steam 1–2 minutes until crisp-tender.
Transfer to a plate.
Sear the chicken. Add the remaining 1 tablespoon oil to the skillet. Add chicken in a single layer. Sear 5–7 minutes, stirring occasionally, until browned and cooked through (165°F/74°C).
Don’t overcrowd; cook in batches if needed.
Add aromatics. Reduce heat to medium. Push chicken to the sides. Add butter and garlic to the center.
Cook 30 seconds until fragrant.
Deglaze and season. Pour in chicken broth and lemon juice. Scrape up browned bits. Stir in remaining Cajun seasoning.
Simmer 2–3 minutes to slightly reduce.
Bring it together. Return broccoli to the pan. Toss to coat in the sauce. Taste and adjust salt, pepper, or cayenne.
If you like it richer, swirl in another pat of butter.
Portion for meal prep. Divide into 4–5 airtight containers. Garnish with parsley or green onions if using. Let cool uncovered 10–15 minutes before sealing.