Cut potatoes into 1" dice. Bring a small pot with potatoes covered in water to a boil. Cook until tender, 12-14 minutes.
Reserve ¼ cup cooking water. Drain potatoes in a colander.
Return to pot and mash with sour cream, half the butter (reserve remaining for gravy), and ¼ tsp. salt to smooth. If needed, add reserved cooking water 1 Tbsp. at a time.
While potatoes boil, prepare ingredients.
Prepare the Ingredients
Peel and halve shallot. Slice thinly.
Stem and coarsely chop thyme.
Pat chicken breasts dry, and season both sides with ¼ tsp. salt and a pinch of pepper.
Cook the Chicken
Place a medium pan over medium heat and 2 tsp. olive oil. Add chicken breasts to hot pan and cook until chicken reaches a minimum internal temperature of 165 degrees, 4-5 minutes per side.
Remove to a plate and rest 3 minutes. Tent with foil.
Reserve pan; no need to wipe clean.
While chicken cooks, cook peas.
Cook the Peas
Place a small pan over medium heat and add 2 tsp. olive oil. Add shallots to hot pan and stir occasionally until tender, 3-4 minutes.
Add peas, thyme, and a pinch of salt and pepper. Stir occasionally until peas are hot, 2 minutes.
Remove pan from burner.
Make the Gravy
In pan used to cook chicken, combine ¼ cup water, white cooking wine, demi-glace, and cornstarch and stir vigorously.
Place pan over medium-high heat and bring to a boil. Cook until thickened, 30 seconds.
Remove from burner and swirl in remaining butter.
Plate dish as pictured on front of card. Bon appétit!