In a large saucepan over medium-high heat, combine all sauce ingredients and mix well. Bring to a boil and reduce heat to low. Let simmer uncovered, mixing occasionally, for 30 minutes. Taste and adjust seasoning as desired.
While sauce is simmering, combine meat rub ingredients in a small mixing bowl. Pat meat dry and slice it into three medium pieces. Generously rub the meat with the spice mix, making sure every area is well covered.
Heat a medium skillet over medium-high heat, and add 1 tablespoon avocado oil. Once the oil is hot, sear meat for 3-4 minutes on each side, or until brown. Place the meat in the crock pot.
Once the BBQ sauce is ready, take it off heat and let cool for about 5 minutes. Pour into a blender and blend until smooth.
Pour BBQ sauce over the meat in the slow cooker and make sure the meat is generously covered.
Cover the slow cooker and set it to cook on low heat for 8 hours.
Remove the meat and place it on a cutting board. Let cool for a few minutes. When cool, using 2 forks shred the meat into bite-sized pieces, discarding any large pieces of fat.
*We like serving this with a slice of bibb lettuce, red cabbage slaw, and chives.