For the natural jus:
1) In a medium saucepan, bring the reduced chicken stock to a boil.
2) Whisk in the butter, thyme, salt, and pepper until combined. Remove from heat.
For the sage and baby spinach mashed potato:
1) In a large pot, boil the potatoes until soft, then drain.
2) In a separate small pot heat the cream, butter, salt, and pepper on medium heat until warm.
3) In a large bowl combine the drained potatoes and the heated cream mixture, whip until smooth. Add the buttermilk, sage and baby spinach. Stir potatoes until the spinach is lightly wilted.
For the chicken:
1) Preheat the oven to 150 degrees C. Remove the skin and bones from the chicken breasts, leaving the wing bone attached.
2) In a large bowl whisk together the eggs, sour cream, mustard, parsley, thyme, garlic, salt, and pepper. Coat the chicken in the seasoned flour and then in the egg mixture. Press the dredged chicken into the bread crumbs.
3) Fry the breaded chicken in a deep-fryer until golden brown, about 10 minutes.
4) Remove the chicken from the fryer and roast in the oven for 15 minutes.
5) Place the cooked chicken on top of the sage and baby spinach mashed potatoes. Serve with natural jus poured around the potatoes.