I believe they call this type of malt whisky a 'sherry monster'. And yes— it is. It's a very good one, too.
Besides sherry, there's black treacle, dried fruits, and sweet maltiness by the bucketload.
Right now, though, it's just a bit much— too rich, too intense, too filling. It doesn't help that I'm recently back from a holiday that involved way too much apple strudel, spent most of today indoors, and and had a big Sunday roast a few short hours ago. I think this would go down better in front of a log fire after a hearty-but-not-excessive supper, rounding off a long day of hiking across some bleak moorland somewhere in the frozen north.
In the mid-90s, the then-entry level Glendronach was one of the very first single malt whiskies I ever tried— perhaps the one that got me into malt whisky in the first place— and I've got a hankering to sample the current 12 year old to see if it brings those memories back (the label design, at least, looks very similar). I remember preferring it to the 15 year old that came out a little later, after the distillery was mothballed. Watch this space.