Peel carrots then cut in quarters, then in half. The carrots should be in 2 to 3-inch pieces. Spread them onto a sheet pan lined with parchment paper. Toss with 2 tsp olive oil and season with salt and pepper. Roast for 15 minutes, tossing them once or twice until the carrots are tender and brown along the edges.
Combine 1 tsp olive oil, vinegar, mustard, garlic, herbs, and salt and pepper in a small bowl or jar. Stir until thoroughly combined.
Pour over the vinaigrette over the carrots and serve.