Preheat the oven to 350°F (175°C).

In a medium bowl, zest and juice one lemon and half from another, then set aside.

Thinly slice another lemon, removing seeds, for the packets.

Lay out large sheets of parchment, dividing lemon, fennel, and asparagus, and place a salmon fillet on top.

Drizzle with olive oil and season with salt and pepper, sealing the packets tightly.

Place on a baking sheet and bake for about 30 minutes, until salmon flakes easily.

While salmon bakes, whisk in garlic, mustard, honey, and remaining olive oil into reserved lemon juice.

Serve by opening packets and drizzling with lemon-dill vinaigrette.