Preheat the oven to 400ºF. Trim the ends from the asparagus and place the spears on a baking sheet. Toss with 1 tablespoon of the olive oil and a big pinch of salt and pepper. Arrange in a single later and roast until bright green and tips are beginning to char, about 10 minutes.

Meanwhile, trim the ends from the grapefruit and then cut away the peel. Section the grapefruit oven a small bowl, catching the juices. Transfer the sections to a separate small bowl. Whisk the remaining tablespoon of olive oil and the Dijon mustard into the grapefruit juice and season with salt and pepper.

Arrange the asparagus on a serving platter. Top with the grapefruit sections, almonds, mint, and feta (if using). Drizzle with the dressing and serve.