Food burnt on a glass top stove can be tricky to remove as it gets stuck to the surface as it burns. The result is a layer of matte black bits that stand out sharply compared to the rest of the shiny glass surface.  The best method to remove black bits is baking soda and vinegar. Sprinkle the stovetop with baking soda, and then spritz it with white vinegar. The mixture will fizzle spectacularly as the vinegar hits the powdery layer of baking soda. Continue until the whole area is coated. Then soak a large towel in hot water. Wring it out and spread it to cover the surface of the stove. Let it work for at least 15 minutes. Then remove the wet towel and wipe the surface to remove any mixture residue.  If any of the raised bumps of debris are still stuck, they would have softened up significantly while soaking. Carefully remove them using a razor blade at a low angle to the stove's surface. Then shine the glass surface using vinegar and a soft cloth.