Preheat the oven to 200°C / 180°C fan (400°F) and line a baking tray with parchment paper.
Add the diced sweet potato and carrot to the tray with 1 tablespoon of olive oil, salt, and pepper. Roast for 15 minutes.
Add the cauliflower florets, garlic, sliced red onion, and taco seasoning to the tray and toss to combine evenly. Cook for a further 20 minutes, adding the chopped almonds during the last 5 minutes of roasting.
While the vegetables roast, whisk together the dressing ingredients in a small bowl: olive oil, lime juice, Dijon mustard, fresh basil, fresh parsley, salt, and pepper.
Warm the grain packet in the microwave according to package instructions.
Toss the warm grains, roasted vegetables, and toasted nuts with the dressing. Garnish with additional fresh herbs, salt, and pepper to taste before serving.