I hadn't planned on making the turbot sliders for my Depot: Biography of a Restaurant review - apparently a big mistake. Dish Online Editor, Alice, politely disguised her outrage, explaining “But they’re the Depot classic!”
I had noticed the turbot sliders mentioned a few times throughout the book. Al says “We have a number of signature dishes, but none bigger than our turbot sliders. Nearly every single table orders them.” Okay okay, I get it; you all love the turbot sliders, and maybe I will too.
I didn't have time to preserve my own lemons (2-3 weeks) but rest assured there are details in the book on how to. One of the great things about Depot is there are recipes for things like stock, tomato sauce, habanero mustard, the aforementioned harissa and many more. Sure you could buy some of these things off the shelf but they probably won’t be as tasty.
I was initially disappointed that there wasn't a recipe for the slider buns until it was pointed out to me that you can buy exactly the same Loaf bakery slider buns that Depot use in the restaurant from most supermarkets. The buns are actually made from a recipe developed by Al Brown and Sean Armstrong of Loaf. Bread is something that will most likely be made much better by a good bakery than you ever could at home due to the advantage of commercial steam ovens and industrial dough mixers. Plus they do it every day! So I didn't mind buying the slider buns.
Back to making things from scratch, I made mayonnaise for the first time ever! It was actually quite simple, however the recipe makes a huge amount! It actually seems as though a few of the recipes are geared towards restaurant use. In fact these have probably been cut down from the quantities they use at the restaurant considering they serve on average 285 sliders a day! I cut the recipe in half to avoid having to build a pool to store mayonnaise in. Yes I even used 4.5 egg yolks (I had a yolk split on me as I was about to add it which was convenient), which still produced a giant 1.2 litres of mayonnaise.
I was in a rush to get the mayonnaise done so I didn't take any photos, but you just put egg yolks, mustard, lemon juice and apple cider vinegar in a food processor and add scary amounts of oil in a steady stream while blending. I know that's what mayonnaise is made from but there is nothing like measuring out 750ml of oil to remind you that you have been eating this weird oil/egg thing for years. It came out a soft buttercup yellow and tasted good, but I felt like I could taste the canola oil a little. The aftertaste seemed to disperse after seasoning properly and resting for a while.
Preserved lemons are so weird. Lemon and salt is a pretty good combo usually, but those two things alone together merged into one soft gooey thing. But I dutifully chopped them finely and added to the mayonnaise with lemon juice. It certainly lifted the mayonnaise to a new plane, with little bursts of lemon, good levels of saltiness balanced with the creamy mayonnaise.
Turbot is not particularly easy to find, I managed to get it from Jimmy the Fish in Ponsonby Central. If you've never seen a turbot before, they're a grumpy looking flatfish covered in spots to camouflage themselves on the sea floor, where they spend most of their time. Unless you're buying line caught turbot, they’re not a great fish to eat environmentally wise as they have probably been caught via trawling. Having tasted them you could probably switch the fish up with anything white and mild.
The turbot fillets got cut into slider-sized portions and fried in a pan on each side until golden. I then put the buns into the same pan to toast (you could do also this on a flat top barbecue) before assembling the slider; bun bottom gets topped with fish, a dollop of the preserved lemon mayonnaise, watercress and a squeeze of lemon juice before placing the top on.
They were great! That preserved lemon mayonnaise makes all the difference in the context of the slider, cutting through the sweetness of the bun without overpowering the fish. The watercress gives an almost spicy undertone along with a burst of freshness. I had a friend over who is a seasoned Depot visitor and she said it tasted just like the Depot slider, her only complaint being “They're hotter usually.” I had given her one of the sliders I had prepared whilst taking photos.
I made a fresh batch and it was spot on. Another taste tester exclaimed “Oh wow it's so delicious, it tastes like a fine dining take on a 'Fillet-O-Fish' from McDonalds.” An argument about how you just couldn't compare the Depot Turbot Slider to a McDonalds 'Fillet-O-Fish' ensued. I have never had a 'Fillet-O-Fish' but I was happy with my Turbot Slider thanks.