Place the foil pan on the grill over indirect heat.
Add beer, kraut, butter and onions.
Cook until the onions start to get nice and soft.
Grill the brats over low to medium direct heat and when they are done put them in the foil pan (Brat Tub) to keep warm.
You can also place the foil pan in an oven heated to 250 degrees to keep brats warm or place brats and kraut mixture in a slow cooker on warm setting.
Serve brats on buns with the kraut, onions and ketchup and/or mustard on top.
Notes
Instead of doing this in a foil pan on the grill you can also do this on the stovetop, in a crockpot or in a Nesco roaster. Get the butter, onion, kraut beer mixture going first and cook until onions are soft. Then add the grilled brats. Perfect for tailgating and easy entertaining!