The Juicy Lucy Burger is a regional classic from Minnesota. You can enjoy this at home with a few simple tricks. No trip to Minnesota for you.
Most cheeses except very hard cheese will melt in the 120-130 range. In other words, it will be liquid after it cooks a little. So a word to the wise, let it cool a little before biting in. The edges may leak a little, just work on your technique next time. Many will add more cheese on top. Fine if you want and it is the “classic” way.