Wash and pat the chuck roast with paper towels to remove moisture. Heat skillet to medium-high. Add olive oil to hot skillet. Dip the chuck roast in flour. Sprinkle freshly ground pepper on each side of roast. Once oil is shimmering, add garlic and roast to skillet. Sear meat so both sides are lightly browned, about 1-2 minutes per side.
Place meat in crock pot. Carefully pour/scrape oil/garlic mixture over meat. Add 2/3 cup water. Choose 10 hour, low-heat setting on crock pot.
After 5 hours of cooking, tie tarragon sprigs together using butcher's twine. Add tarragon to crock pot. Sprinkle sesame seeds evenly over roast. Continue cooking.
About 1 hour before end of cooking time, add julienned bell pepper to roast.
At the end of cooking time, the beef should be very tender. Use tongs to pull apart. Serve on a bed of greens and/or crusty bread. Enjoy!