Heat garlic and olive oil in skillet, add ground beef. Cook over medium heat until browned. Drain fat, add salt and pepper to taste. Scrub and prick potatoes. Bake at 400' for 1 hour or until done.
When cool enough to handle, cut a thin slice from the top of each potato, scoop out the pulp, leaving a 1/4" shell. Place the pulp in a medium bowl and set aside.
Place the potato shells on a baking pan.
Add milk and butter to pulp and beat until smooth. Add 1/2 cup of cheddar cheese. Place into a storage bag, express air form bag and zip close. Cut a tip from the corner of the storage bag. Fill potatoes with cooked ground beef. Pipe potato mixture atop hamburger. Sprinkle with remaining 1/2 cup cheddar cheese.
Return to oven and bake at 400' for 10 minutes, or until heated through and cheese is melted.