Place ground meat in a large bow.
Add in the garlic, onion, jalapeno, breadcrumbs, egg and yolk and mix until just incorporated.
Add in the Worcestershire, barbecue sauce (or ketchup) and season generously with salt and pepper.
Form into classic meatloaf shape.
Place meatloaf on a double or triple folded piece of foil large enough to have room on the sides and ends (so you can almost envelope the meat).
Heat your grill to high and place the meatloaf (in foil) onto the grill. Leave the foil mostly open almost like your cupping your hands under something. This will allow the sir to circulate around the meatloaf and crisp it up.
Cook on direct heat for 10-12 minutes, then continue cooking on indirect heat (turn the burner off below where the meatloaf is placed) until done. Use a digital thermometer and remove meatloaf when temperature is 155 degrees in the center of the loaf. The temp will continue to rise after you pull it off the grill (to 160). Pulling it at 155 ensures a juice loaf.
Choose to brush your meatloaf a few times with additional barbecue sauce. Sometimes I actually FLIP the meatloaf, directly onto the grill to crisp the top and speed up cooking time...Plus get those grill marks! You just need to use a hefty spatula and flip gently but quickly. Up to you.
Allow the meatloaf to stand for 5-8 minutes, cut into it and enjoy!