I have a Cuisinart belgian waffle iron that I've used successfully in the past. I made blueberry waffles, using fresh berries that I mixed into a standard waffle recipe. Also, I lightly brushed the iron with canola oil first. What a mess - waffles stuck horribly. Ended up with mostly squished waffles and a waffle iron (non-stick) with seriously stuck-on gunk, that was a pain to clean up. What went wrong?