Apply olive oil generously to outside of roast. Coat with your seasoning mixture (feel free to ad lib here with flavors you enjoy).
Sear roast in a skillet on all sides 30-60 seconds until a nice brown crust forms.
Place your 2 cups of hot water and the onion soup mix into the crock pot. Transfer browned roast to crock pot.
Cook on low 4-6 hours or high 2-3 hours. NOTE: check the temperature often if able – you do not want to overcook your roast. For a medium roast, take it out when at 135 deg and let it rest until 145 deg. Thinly slice the roast against the grain OR pull apart with fork.
In a skillet over medium heat, caramelize onions and mushrooms in 2 Tbsp of butter. Once finished, place a serving of meat with a serving of the vegetables and cover with a piece of cheese. When cheese is melted, transfer to your hoagie.
For an added twist I use a red pepper mayo on the sandwich. It adds a nice kick of sweetness. (see recipe above)
Your au jus should be waiting for you in the bottom of the crock pot! No additional work needed for this. Indulge and enjoy!