How do I clean burnt milk from a glass-ceramic stove?
There are a couple things you can try.  I'll list them from most conservative to 


Let it cool. Squeeze some cleaning paste on it, and cover with a
paper towel. Wet the towel, let it soak, then buff it with the paper
towel or a non-scratch scouring pad.
Magic Eraser-type melamine foam sponge
Plastic razor blade scraper, sometimes called "Safe    Scraper" sold
at hardware and automotive stores
Metal razor blade scraper