Preheat your oven to 375°F (190°C). In a large skillet, heat olive oil and butter, season sirloin with salt and pepper, and sear until browned (6-8 minutes).

Add chopped onions and carrots to the skillet, sauté for 4-5 minutes until onions are translucent.

Sprinkle flour evenly over the mixture, stir well, and cook for 1-2 minutes to thicken.

Pour in apple cider and beef broth, scrape any browned bits, bring to a gentle boil, transfer to a Dutch oven, cover, and bake for 60-90 minutes.

Peel and chop potatoes, boil in salted water for 20-25 minutes until fork-tender, drain, mash with milk, sour cream, cheddar, and chives.

Serve by layering cheddar mashed potatoes on plates, topping with stew and garnishing with additional chives.