Finally made it to Culvers, and had a double Butter Burger with Cheese, an order of rings, and a small custard. Of the three, my favorite was the burger, which was a delicious mess, the meat full of charred edges.
But the revelation was Kopp's in Milwaukee, which makes the best frozen custard I've ever had. My friend and I both tried today's special, caramel cashew (a vanilla base with caramel and huge pieces of excellent cashews). If the burgers are anywhere near this level, this is one of the great fast food places in the country.