This is the most premium of Bushmills whiskies - aged for 19 years in oloroso sherry and bourbon casks, then finished for another two years in Madeira casks. I've tasted this a couple of times, I believe the first time was courtesy of @Victor, then again at an Irish pub somewhere - I've always loved it but never really spent time with it. Apparently no more than 900 cases are released each year. This one is the 2018 release, bottle no. 03573.
The colour is a medium gold. On the nose this is very nutty - almonds, walnuts and red peanut skins. Dark grapes (and dark raisins too....and dark chocolate). I'm positive there is a hint of peat smoke in the background (they do peat their malt sometimes). Black liquorice. A touch of mint. Leathery. Ground espresso. Maltier and more herbal with water. Stunning.
On the palate - unbelievable. It is constantly changing from rich to fruity to sherried to nutty and back again. Where do I begin.... Brazil nut, liquorice all-sorts, coffee cake, vanilla bean, black cherry and green banana. Buttery. Luscious mouthfeel. Water brings all the sweet malt upfront. One of the greatest palates - if not the greatest - in Irish whiskey.
The long finish is smoky with cinnamon, beef stock and black pepper. Quite simply one of the greatest whiskies you will ever try, IMHO. I've been using the word elegant a lot in these Irish whiskey reviews, and this continues that theme admirably. Winner of Irish Single Malt of the Year in Jim Murray's 2020 Whisky Bible (for once he's right).