RECIPE - Mackerel in a Sweet/Sour Sauce (Sororoca com molho tarê)

Last week, Flavors of Brazil reported (here) that famed chef Alex Atala's D.O.M. restaurant in São Paulo had been named the seventh-best restaurant in the world. In celebration of this achievement, Brazilian food magazine Prazeres da Mesa published seven recipes from D.O.M. in their online edition.

All the recipes (in Portuguese only) can be found by clicking here. Below is one of the seven recipes, which we've translated and adapted for our readers. We decided that some of the other recipes from D.O.M. really are not meant for home kitchens - dishes such as Rã com purê de couve flor e curry negro (Frog with cauliflower puree and black curry) - or depended on ingredients unavailable outside Brazil - Ovo pochê com tucupi e mandioca (Poached egg with manioc and tucupi sauce). The recipe below can be made in almost any home kitchen and calls for ingredients that are universally obtainable. The fish specified is mackerel, which is widely available  It does include xanthan gum, a sugar-based food thickener, which can be found at most restaurant supply stores, and the herb purslane. We've seen purslane for sale at North American farmer's markets, but since it's a garnish only in this recipe it can be eliminated or other herbs can be substituted.
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RECIPE - Mackerel in a Sweet/Sour Sauce (Sororoca com molho tarê)
Serves 4

4 fillet pieces of mackerel, with skins on, each about 4 oz. (120 gr)
1 1/2 Tbsp (20 gr) granulated white sugar
1 tsp (5 gr) xanthan gum
1/4 cup (50 ml) water
3 Tbsp (30 ml) soy sauce
4 tsp (20 ml) rice vinegar
salt, pepper to taste
extra-virgin olive oil
purslane
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In a small saucepan, combine the water, soy sauce, vinegar and sugar. Place over very low heat and cook for 15 minutes, without letting the mixture come to the boil. Remove from heat, let cool to room temperature and reserve.

Mix the cooled sauce with the xanthan gum in a large mixing bowl. Using a hand blender or mixer, beat for five minutes at high speed until the mixture thickens. Reserve.

Season the fish with salt and black pepper to taste. In a non-stick frying pan heat a small amount of olive oil until hot but not smoking. Cook the fish, skin side down first, for a few minutes on each side, or until the skin is crispy and the flesh is just beginning to flake. Remove from the heat and keep warm.

Reheat the thickened sauce briefly in a small sauce pan.

Place one fillet on each of four plates, skin side up. Glaze the skin with the warmed sauce. Using a teaspoon, draw a line of sauce on each plate near the fish, then add a sprig of purslane to complete the dish. Serve immediately.