1. Preheat the oven to 375 degrees F. Soak the toothpicks in water as you prepare the other ingredients so they don't burn in the oven. Rinse and drain the water chestnuts.
2. Spread the brown sugar out on a plate or shallow bowl.
3. Cut the bacon strips in half (right in the middle), and press one side of each bacon strip into the brown sugar.
4. Spread the other side of bacon with 1/8-1/4 tsp of the whole grain dijon mustard.
5. Place a water chestnut on top of the mustard side of the bacon strip and roll it up, securing the bacon with a toothpick. Repeat with the remaining ingredients.
6. Place all of the bacon wrapped water chestnuts onto a baking sheet and roast for 20 minutes, until the bacon has cooked through and the brown sugar has caramelized.
7. Serve and enjoy!