Maple syrup & maple sugar bake up very similarly to cane sugar. For the simplest substitution, use maple syrup for oil based cakes and maple sugar for butter based cakes, but either can work in either situation.
Maple Syrup: In the case of maple syrup use about ¾ the volume of cane sugar and then reduce the other liquids to accommodate for the extra liquid. If there is water in the cake you can reduce by an amount equal to the amount of maple syrup. The same goes for milk, but in that case you want to increase the fat by a couple tablespoons for each cup of reduction to account for the lost fat from the milk. If the only liquid is oil, start by leaving the volume the same, but you can generally reduce it by about ⅓ if needed.
Maple Sugar: In the case of maple sugar, a one-to-one substitution generally works just fine. However, maple sugar doesn't dissolve as readily as cane sugar so it helps to cream the maple sugar and butter for a minute or more longer than you would cane sugar. Creaming for a shorter period of time will yield a sandier texture.
Substituting Maple Sugar for Maple Syrup: Generally, it's ½ cup of maple sugar to 1 cup of maple syrup.
Depending upon the recipe it may be necessary to increase the liquid by ¼ cup if you're switching to maple sugar from syrup.
See how maple is more than just pancakes and breakfast!