Begin by melting the butter in a pan. Once bubbling, add in the onions and spices. Cook on low heat for 20 - 30 minutes until you get a good browning. Remove from pan and set aside.

Next, add the rye bread to the same pan. Cook on both sides until nice and crispy. Remove from pan.

Now add the ground beef patty to the pan. Smash down a little to get more surface area. Cook until medium inside temperature. Just before the burger is done, add the mozzarella to each patty and cover the pan with a lid. Cook until the cheese is nice and melty.

To assemble, take the burger and add too the rye bread, top with a generous amount of onions and add as much ketchup as you like. Enjoy!