Preheat oven to 400°F/200°C. Prepare a pan lined with baking paper or a silicone mat.
Peel and slice the sweet potatoes into 0.5-inch/1.5-2 cm long cubes. Peel and slice the carrots into 0.25-inch/1 cm long cubes. Slice the red onion lengthwise into eighths. Place the chopped vegetables on the baking pan, drizzle over olive oil and season with salt. Mix gently so that all the vegetables are covered in oil and flatten them into one layer. Bake for 20-25 minutes until the vegetables are ready and lightly golden.
At the same time, cook the quinoa. In a small pot, heat olive oil. Add the quinoa and salt, and sauté for 2-3 minutes while stirring. Add 2 cups of water, stir and cover with a lid. Bring to a boil, then lower to a low heat and cook until all the water is absorbed into the quinoa, about 25 minutes. Leave the quinoa pot covered for at least 5 more minutes after the end of cooking.
Prepare the dressing - in a jar with a lid, place all the dressing ingredients. Close the jar and shake until a smooth dressing is obtained.
Place all the salad ingredients in a suitable bowl - cooked quinoa, baked sweet potato and carrot cubes, baked red onion and chopped parsley. Pour over the dressing and mix gently. Enjoy!