Lay them on a large cookie sheet. Drizzle on the 2 Tablespoons olive oil.
Sprinkle with kosher salt & pepper.
Bake for about 10 minutes or until tender but still firm & moist.
While the asparagus are roasting, whisk the dijon mustard & lemon juice together in a small bowl. Slowly drizzle in the olive oil & whisk till emulsified.
When the asparagus are done cooking, transfer to a serving dish and toss with the vinaigrette.