The Dutch make a few dishes similar to what you describe. (note: I'm assuming that your 'like a cordon-bleu' doesn't mean it's breaded stuffed chicken, as you mentioned it was vegetarian)
If they're smaller (one or two bites), they'd be bitterballen. They're normally meat-filled, but they can be filled with vegetables, too.
If they were larger, they'd be kroketten
update: to clarify, I am not Dutch, and moved from the Netherlands 30 years ago. As a non-native Dutch speaker, I had (possibly incorrectly) assumed that 'kroketten' was a class of food / style of preparation. From Marc Luxen's answer and Cerberus's comments, I'm going to assume that the term is similar to American 'burger'. If someone ordered a 'burger' and you gave them a veggie burger, it'd not be what they expected. (and similarly, we have 'cheeseburger', 'veggieburger' and other compound words that are more specific)
(and there hadn't been complaints about people answering in comments, I wouldn't have made this an answer ... as I had to make an assumption about what made it 'cordon bleu'-like. I assumed something stuffed, then breaded & fried, possibly with cheese or other dairy).
... and I'm making this community wiki so that any native Dutch person can correct it, as I don't know how to undo it being marked as correct.