Preheat the air fryer by selecting Roast at 400°F / 205°C and setting the time to 15 minutes.
While the air fryer preheats, prepare the salmon. In a medium bowl, whisk together melted butter, honey, Dijon mustard, and Herbs de Provence mix.
Place the salmon fillets on a plate or cutting board and brush the butter mixture evenly over the fillets. Sprinkle with salt and pepper, and top each fillet with a slice of lemon.
Once the air fryer displays the Add Food prompt, open the basket and carefully place the salmon fillets inside. Close the basket and press Start.
While the salmon cooks, prepare the asparagus. Place the asparagus on a baking pan, drizzle with olive oil, and season with salt and pepper. Toss to coat and set aside.
When the air fryer displays the Turn Food prompt, open the basket and arrange the asparagus around the salmon. Close the basket and let the cooking cycle continue.
Once the cooking cycle ends, remove the air fryer basket and let the salmon and asparagus rest for a couple of minutes.
Serve the salmon fillets with asparagus evenly on each serving plate. Enjoy!