Instant Pot Beef Stew

1 1/2- 2 lbs. stew meat (or chuck roast cut into small pieces)
salt & pepper
2 Tbs. butter
8 oz. small white mushrooms
1 medium onion, diced
3 stalks celery, cut into bite sized pieces
4 large carrots, cut into bite sized pieces
2 Tbs. pepperoncini (less if you don't like heat, more if you do)
2 Tbs. tomate paste
1 Tbs. sugar
1 packet ranch seasoning mix (3 Tbs.)
2 Tbs. Worcestershire sauce
3 Tbs. cornstarch
2 c. beef broth plus 2 bullion cubes
1 tsp. minced garlic

For the mashed potatoes:
2 lbs. russet potatoes
3 c. cold water
1 1/2 tsp. salt
1 Tbs. minced garlic
1 tsp. rosemary
1/2 tsp thyme
1/4 c. butter, melted
1/4 c. sour cream
4 oz. cream cheese

Instructions:
1.  Turn the electric pressure cooker on the sauce/brown setting.  Melt the butter in the pot.  Add the meat, season with salt and pepper.  Sear the meat on all sides.  Turn off sauce setting.

2.  Mix the beef broth with the cornstarch then add to the pot.  Add all remaining ingredients to the pot.

3.  Select the stew setting and time for 35 minutes.  NATURAL release for at least 15 minutes.

4.  While the stew is cooking, prepare the mashed potatoes:
   
     Peel the potatoes and quarter them.
   
     Boil the potatoes in the water until fork tender, or if you have another instant pot, add the potatoes,  
     water, salt, garlic, rosemary, and thyme into the instant pot.  Cook on manual on high pressure for
     8 minutes.  Vent, drain the potatoes.

     Mash the potatoes using a potato masher or hand mixer.  Mix in the melted butter, sour cream,
     cream cheese, and additional salt and pepper if needed.

5.  Serve the stew over the mashed potatoes.