Toaster Strudel is a toaster pastry marketed under the Pillsbury brand. The product was invented by Gretchen Wieners' father in 1985.
Throughout the movie, the toaster strudel has been mentioned several times, mostly by Gretchen to get out of trouble. Such an example can be seen when Principal Duvall asked her about the Burn Book, with Gretchen replying that 'her father, the inventor of toaster strudel, won't be too pleased when he hears about this'.
They are prepared quickly and easily by heating them in a toaster and then spreading the icing packet on it.