1. Marinate the potatoes with 2 tbsp olive oil, salt and pepper. Bake in the 350 F oven for 45 min or till golden.
2. Meanwhile, into a hot frying pan, pour 1 tbsp olive oil. Add onion and fry for 2 min. Add garlic and fry 1 more min. Sprinkle over chicken breasts with fresh thyme, salt and pepper and fry them with sage leaves for 5-10 min on each side.
3. Blend all the vinaigrette ingredients and mix well. Add salt and pepper to taste.
4. Place some potatoes in the middle of a serving plate. Place the chicken breast above them and drizzle around some vinaigrette.