Powdered sugar is a super fine sugar, finer than even castor sugar. It is often termed as 10X sugar, confectioner's sugar or icing sugar. In France, it is called Sucre Glace. The size of the sugar crystal varies 10X sugar is usually 0.010 mm, while confectioner's sugar is 0.060 mm, and icing sugar is 0.024 mm.t is a type of granulated sugar that has superfine granulated crystals, usually 0.35 mm. The term castor or caster sugar is mainly used in UK English and its Commonwealth countries. In North America, it is sold as super fine sugar.
Standard baking temperature is 350 degrees, which works just fine for fish. But you can get away with setting the temperature even lower. This extends the cooking time, which may help if other ingredients in the dish need more time to cook.
Give the fish a little rub down with oil, transfer it to a rimmed baking sheet (I like to line the sheet with parchment for easier cleanup later), and roast it until a thermometer inserted into the thickest part of the fish reads about 135Â°F.