Instant Pot Instructions:

1. Turn Instant Pot to sauté setting. While pot is heating up press the kosher salt and pepper all over the roast. When Instant Pot says HOT on the display add in 2 Tbsp of the oil. Add the roast to the pot and brown on one side for 3-4 minutes and then turn over and brown for another 3-4 minutes. 
2. Add in the coke and scrape the bottom of the pot so that nothing is sticking. Turn off the Instant Pot. 
3. Cover Instant Pot and secure the lid. Make sure valve is set to sealing. Set the manual/pressure cook button to 60 minutes (80 minutes for frozen roast). 
4. While roast is cooking add onions, carrots, potatoes, remaining 2 Tbsp of oil and onion soup mix to a large ziplock bag. Seal the bag and shake to coat vegetables. Store in the fridge.
5. When time is up on the Instant Pot perform a quick release by moving the valve to venting. Remove the lid.
6. Add in the vegetables. Cover Instant Pot and pressure cook for another 5 minutes. When time is up let pot sit for 15 minute or longer and then move valve to venting to release any remaining pressure. Remove lid. 
7. Scoop roast and vegetables onto a platter.
8. Turn your Instant Pot to the sauté setting. In a small bowl stir together 2-3 Tbsp of cornstarch with 3 Tbsp of water, until smooth. Then pour the mixture into the Instant Pot. The cornstarch mixture will thicken up the gravy quickly. 
9. Serve gravy with roast and vegetables. 

Slow Cooker Instructions:

1. Heat a pan on the stove over medium high heat. Press the kosher salt and pepper all over the roast. Add in 2 Tbsp of the oil. Add the roast to the pan and brown on one side for 3-4 minutes and then turn over and brown for another 3-4 minutes. Add to the slow cooker.
2. Add in the coke. 
3. Add onions, carrots, potatoes, remaining 2 Tbsp of oil and onion soup mix to a large ziplock bag. Seal the bag and shake to coat vegetables. Dump the vegetables into slow cooker.
4. Cover and cook on low for 8-10 hours. About 8 hours into the cooking time take a small bowl and stir together 2-3 Tbsp of cornstarch with 3 Tbsp of water, until smooth. Then pour the mixture into the crockpot. 
5. Scoop roast and vegetables onto a platter. and serve with gravy.