How much Marshmallow fondant would I need to cover an 8 inch round cake? This is based on the recipe on this site?

good question! I have been practicing with this fondant lately using the small batch, (1c. mm, 1 tblsp. water, and 1 1/2 c. p.sugar) and that has been making enough to cover the round 6" x2", one layer, with a small swag. It may be that I'm not rolling it thin enough. I would think doubling that would do it, but there are decorators on here who have done it and will know more than I do. Now, I have a question about fondant since you have raised this question...
When rolling it out, how big of a circumference do you roll it according to cake size to keep the "waves" from being on the cake sides?

When using any type of fondant you need to roll it out to the size of your cake plus the height of your cake x2. example - for an 8" round cake 3" high you would need to roll the fondant to at least 14" or 8" + 3" + 3" = 14". If you are getting "waves" you can smooth the fondant down on the sizes and use a knife or pizza tupe cutter to trim the excess at the bottom. Hope this helps!

Debbie

I used the MM fondant and found that you need to double the batch if you want enough to cover an 8 inch double layer cake. This recipe makes a small amount which is great for misc things but you need to at least double it for covering anything bigger than 6 inches.

Good luck, it is great stuff, I am using it again this week for my Wilton Class 3 end of course cake.

Shayla

Definitely make a double batch for that size cake. Otherwise you would be rolling it out too thin and would then have to worry about tearing it or being able to see thru it...and that doesn't look good!

I just did my first MMF cake. I had a 6", 8", and 10" round stacked design wedding cake. (All double layers) I doubled the recipe and still had some left. (Which my kids ate!) Hope this helps!