Why did my toasted acorn squash seeds smell like chocolate? I recently toasted some acorn squash seeds in my toaster and, to my surprise, when I opened the toaster I got the unmistakable aroma of chocolate. A friend readily confirmed that they did indeed smell like chocolate, so I'm pretty sure this wasn't just wishful thinking on my part. Alas, they didn't taste like chocolate...

I didn't do anything fancy to the seeds before cooking them - I just washed them and broiled them in my toaster at 450F for about 5-10 minutes.

I assume that there is some chemical reaction taking place that produced the same compound in the seeds that also occurs in roasted chocolate, but I have no idea what it is or why I'd only have this happen with acorn squash seeds and not, say, toast.

Any ideas about what caused this?

Thanks!
The difference between carmelization and the Malliard Reaction

When cooking seeds and nuts, you are essentially carmelizing various basic sugars and amino acids (the components of protiens) via the malliard reaction.  This is what gives a grilled steak a different flavor than a boiled one, just like white table sugar has a different flavor from carmelized sugar via carmelization.

When cooking anything you are trying to add flavor to, there is a point where it goes from tasty to not-tasty.  Think of a charred steak or burnt caramel.  Some items that we expect a certain amount of bitterness from (coffee, chocolate, etc) are pleasant to smell because they smell like they will taste; a little bitter and likely robust.

When you are expecting a buttery, nutty taste, the smell of chocolate or coffee may seem pleasant, but it tends to signify the seeds have cooked to that doness, which is probably not an ideal one for that item.  A medium-well tuna steak may smell nice, but (arguably) won't taste as nice as a rare/medium-rare steak.

You essentially burnt your seeds. (no snickering!)

I would recommend in the future you pull them out of the oven a few minutes before they smell like you want them to.  They will keep cooking on or off the pan for a couple minutes due to residual heat.