I am making a filling for a cake that calls from shredded coconut. I could only find desiccated unsweetened coconut, which is very light and in tiny pieces. Can I use this the same way? Will it absorb too much liquid and make the filling too thick?
I wouldn't try it. The unsweetend has a dryer texture, and it primarily used for things like coconut shrimp, since it makes a good dry coating. What you want is a far moister coconut for filling, and the sweetened shredded stuff is what you are looking for. Don't know where you live, but this is a common baking items in most grocery stores.
You can try to use it, but the dryness is going to take its toll as well as the lack of sugar, so I really don't think it is worth it. Keep shopping.
You can use the dessicated, it won't absorb enough liquid to thicken your filling beyond what you want; dried coconut doesn't have much, if any, absorption power. But the tiny shreds won't give you much texture either, and possibly not much flavor, depending on the quality. Did the recipe call for using sweetened coconut and you couldn't find that, or did it call for fresh coconut?
Would you consider using a fresh coconut? I know they can be a pita to prep but it's generally better flavor than desiccated, you can control the size of the grate, and any remaining coconut can be frozen successfully, either grated or left in pieces.