From the Canadian Living Test Kitchen. Real Cheddar cheese and crispy bacon (add extra if you like) make this traditionally Canadian diner-style burger taste even better at home. Serve in hamburger buns. Canadian Living Magazine, July 2005.
In large bowl, beat egg with water; stir in bread crumbs, grated onion, Dijon mustard, garlic, salt and pepper. Add beef; mix just until combined. Shape into four 3/4-inch (2 cm) thick patties. (Make-ahead: Layer between waxed paper in airtight container and refrigerate for up to 24 hours or freeze for up to 1 month. Thaw in refrigerator.).
Place on greased grill over medium heat; close lid and grill, turning once, until digital thermometer inserted sideways into centre reads 160°F (71°C), about 15 minutes.
Top each burger with cheese and bacon; grill until cheese melts, about 5 minutes.