Preheat your oven to 400°F (200°C). Line a large 18x13-inch rimmed baking sheet pan with unbleached parchment paper for easy cleanup and even heat distribution.

In a small bowl, whisk together the honey, whole grain Dijon mustard, smooth Dijon mustard, minced garlic, and 1 tablespoon fresh lemon juice until smooth and emulsified.

Arrange trimmed asparagus spears on one half of the baking sheet. Drizzle with 1 tablespoon olive oil, season with 1/4 teaspoon sea salt and a pinch of black pepper, then toss directly on the sheet and arrange in a single layer.

Place salmon fillets skin-side down on the other half of the sheet pan, leaving 1 inch of breathing room between fillets. Lightly brush salmon tops with the remaining 1/2 tablespoon olive oil, then season with the remaining 1/4 teaspoon salt and pepper.

Using a silicone pastry brush, generously spoon and brush the honey mustard glaze over the top and sides of each salmon fillet. Tuck thin lemon rounds around the asparagus and salmon.

Roast on the middle rack for 12 to 14 minutes. If desired, switch oven to BROIL for the final 60 to 90 seconds to bubble and lightly caramelize the honey glaze (watch carefully to prevent honey from scorching).

Remove sheet pan from the oven when salmon reaches an internal temperature of 125°F to 130°F (52°C to 54°C) for medium tender flakes. Let rest for 2 minutes on the warm sheet pan, scatter fresh chopped dill on top, and serve warm immediately.