Drizzle 1 Tablespoon of the Olive Oil on a rimmed baking sheet, and using your hands, spread it thoroughly over the sheet.
Trim and halve the Brussels Sprouts, and place in a large bowl. Add 1/2 tablespoon of the Olive Oil, and 1/2 teaspoon salt, and toss well.
Pour the Brussels Sprouts on the baking sheet, and arrange them all cut-side down. Place in the oven, and bake for 8 minutes.
While the sprouts are baking, cut the carrots into 2 inch matchsticks. I cut the carrot in threes, then make planks about 1/8" thick. Then, I cut the planks into strips, again, 1/8" thick.
Trim the fennel of it's bottom, and the top parts, leaving the bulb. Slice down the middle of the fattest side, and cut the core out. Cross-section the half into two pieces, length-wise, and then cut into thin strips.
Place the carrots and fennel in a small bowl, and drizzle with the remaining olive oil and salt.
Once the sprouts have passed the 8-minute mark, pour the carrots and fennel over the sprouts, leaving the sprouts face down and not moving them.
Return the pan to the oven to cook for 2 minutes more, until the carrots and fennel are only slightly cooked, and still very crisp.
Remove the sheet from the oven, and pour the sprouts in a large bowl. Add the sauce and toss. Garnish with fennel fronds. Serve Immediately.