Icing sugar is finely ground sugar, which when added to whisked egg whites makes Royal Icing.
Royal Icing sugar is finely ground suger pre-mixed with dried, pasteurised egg white. This is good if you want to avoid the "risk" associated with raw eggs. However, the ratio of egg white to sugar is fixed and the only adjustment which can be made is to add water (or lemon juice/glycerine) to vary the texture.
If you are making icing, yes. If you are making a meringue, no.
Fondant
Marzipan under fondant icing makes the cake too sweet, because fondant icing makes the cake too sweet on their own. It is better to use a buttercream with less sugar.
No. You do not have to put icing under the fondant on a cake. You can bake a cake and not put any icing on it and just put fondant on it if you wish. No law forces you to put icing on the cake. With that said, How do you plan to stop the icing at the edge of the fondant? Which will you apply first? Normally sugar in the the icing causes it to stick to the cake and also causes the fondant to stick to the icing. So if you have messy people eating your cakes and do not want the fondant to fall off the plates onto the rug as they walk around the living room at a party, it would be best to use icing as a glue.
Icing sugar is also known as confectioner's or powdered sugar. It comes in different grades of fineness, 10X often being the highest grade found on grocery shelves. Whatever the grade, it makes for smooth icings, especially when sifted and combined with cream cheese. It also makes an excellent drizzle frosting -- as for sticky buns or pound cake -- when combined with milk, cream or fruit juice. Fondant icing is not really an icing but a sugar, and it's 100x finer than confectioner's sugar. It is used to make fondant, an old-fashioned kind of candy that is easy to make and has a very firm texture, almost like modeling clay. Kept in the refrigerator, fondant lasts for months. It can be flavored with extracts and colored with food coloring. Its unique texture means it can be molded around nuts or candied fruit, and dipped in chocolate and rolled in cocoa or coconut... the possibilities are endless. It makes for very special candies that are pretty and taste good, too.
Mix together vanilla or chocolate icing with powdered sugar.
To make marshmallow fondant, a common ratio is about 1 cup of icing sugar for every 100 grams of marshmallows. Therefore, for 300 grams of marshmallows, you would typically need around 3 cups of icing sugar. Adjustments may be necessary based on humidity and consistency preferences.
Rolled-in-fat dough is generally creamed butter (it can also be shortening), with a small amount of flour added to it. It is used as the fat layer to make puff pastry, danish and croissant doughs.
Icing sugar is also known as confectioner's or powdered sugar. It comes in different grades of fineness, 10X often being the highest grade found on grocery shelves. Whatever the grade, it makes for smooth icings, especially when sifted and combined with cream cheese. It also makes an excellent drizzle frosting -- as for sticky buns or pound cake -- when combined with milk, cream or fruit juice. Fondant icing is not really an icing but a sugar, and it's 100x finer than confectioner's sugar. It is used to make fondant, an old-fashioned kind of candy that is easy to make and has a very firm texture, almost like modeling clay. Kept in the refrigerator, fondant lasts for months. It can be flavored with extracts and colored with food coloring. Its unique texture means it can be molded around nuts or candied fruit, and dipped in chocolate and rolled in cocoa or coconut... the possibilities are endless. It makes for very special candies that are pretty and taste good, too.
2 cups to 2 tablespoons (but milk tastes better!)
Possibly to aid crystallisation to turn the sugar syrup into a 'fondant' (a substance kind of like thick white icing).
Well first of all you need to have a particular shaped -out icing spread and if you watch many ADS (advertisments).You can see they always will say about icing spreaders. Cover the iced cake with a sheet of wax paper and smooth it out with your hand. Refrigerate the cake for awhile and peel off the wax paper once the icing has hardened. You will know it is ready when the icing does not stick to the paper. Another way to have the effect of smooth icing is to use fondant. It is like dough, but it is made mostly out of sugar and its easier than trying to get icing smooth..