in large bowl, mash bread, milk, garlic powder, salt and pepper into smooth paste
add beef and lightly knead mixture until well combined
divide meat into 4 equal portions
using half of each portion, encase cheese to form mini burger patty
mold remaining portion around the mini burger, seal edges to form a ball
flatten ball to form 3/4-inch-thick patty
cover and refrigerate for at least 10 min
heat grill - for 10-15 min on high
turn grill to medium
grill and cook without pressing on them - 12 to 16 minutes, flip halfway through
tent with aluminum and let rest for 5 minutes
