Set Instant Pot to saute.
Season roast with salt, pepper and garlic powder.
Add canola oil to Instant Pot insert and sear roast on all sides; about 3 minutes per side.
Add broth and bay leaf to Instant Pot and close the lid, making sure the pressure valve is set to seal.
Set Instant Pot to Manual and adjust time to 100 minutes.
Once finished, release pressure and shred roast with two forks.
While roast is cooking, caramelize onions with butter and set aside.
Set oven to broil and place sandwich rolls, cut side up, on a baking sheet. Spread a light layer of butter on rolls and toast for 2-3 minutes, until just starting to brown. Remove from oven and add meat, cheese and onions. Return to broiler until cheese is melted, about 1–2 minutes. Serve with warm au jus for dipping.
Slow Cooker variation
Combine all ingredients in a slow cooker and cook on low for 6-8 hours or on high for 3-4 hours.