Cut pork shoulder into 3-4 inch sections. Rub pork shoulder in mustard, rub, and salt. Let sit for 1 hour up to 24 hours.
In a large dutch oven over high heat add oil. Working in batches sear pork.
Add all the pork back into the pot and add the bourbon and chicken stock.
Set the oven to 300F and cook until pork shreds easily with a fork, about 3-4 hours.
To make the BBQ sauce heat a medium saucepan over medium high heat. Add the olive oil and the onion and cook until softened, about 5 minutes. Add the remaining BBQ sauce ingredients and let simmer on medium low for at 20 minutes, stirring occasionally.
Shred the pork and toss in 1 cup of BBQ sauce. Serve on a toasted bun with pickle slices and extra BBQ sauce. Enjoy!