Place the beef in a bowl. Sprinkle with 1 teaspoon salt and 1 teaspoon pepper. Toss to coat evenly. In a large frying pan over medium-high heat, warm the canola oil. Working in batches if necessary, sauté the beef until browned on all sides, about 5 minutes. Remove from the pan and set aside.
Add the onion and garlic to the pan and sauté over medium-high heat for one minute. Add the curry paste and stir until it is fragrant and coats the onion and garlic, about 30 seconds. Add the coconut milk and deglaze the pan, stirring and scraping up the browned bits on the bottom of the pan with a wooden spoon. Stir in the fish sauce, lime juice and brown sugar. Bring to a boil.
Transfer the beef to a slow cooker and add the coconut milk mixture. Cover and cook until the beef is very tender and the sauce is thick but still fluid, 3 hours on HIGH or 6 hours on LOW. About five minutes before the beef is done, stir in the bamboo shoots.
Spoon the curry onto warmed plates or into a large serving bowl. Garnish with the mint and serve at once.