i made the mmf today for the first time. when i tried to roll it out it seem to break pretty easily. it isn't as "taffy" like as store bought fondant is. did i make it right or am i missing something.

Which recipe did you use? I use the YouTube method of one cup of marshmellows, 1/2 T water, and 1/2 bag of confectioner's sugar. I put my sugar on the greased counter, then dump my microwaved MM int the sugar, that method works the best for me: the MM Only take the amount of sugar they need to get a great consistency. I had to make several batches to learn the "right" amount to make my MMF roll out nicely.

I used the same video. I needed more so i used the full recipe. I also added the color in the melted mm. i needed black. i noticed that if i use shortening to roll it out it worked better, but i don't see how it would work to roll out big enough to cover a cake. it just seems to break to easily when i try to handle it after it is rolled out.

I'm guessing you added a bit more powdered sugar than needed. The same thing happened to me the first time I made MMF, because I didn't know exactly how much sugar it needed. It called for 1-2 lbs. The second time I made it I didn't use nearly as much sugar and the fondant wasn't breaking. It was very pliable. If the MMF is breaking though, you can put it the microwave for around 10 seconds, or a little more. That's what I did and it worked. I hope this helps :]

Sometimes the black color will make it act weird too. Black and red both seem to do that. I think it's because of the glycerin in the color and the amount it takes to make the right shade.

The recipe that I use is 16 oz marshmallows, 2lb powdered sugar and 1/4 cup of water, plus crisco to grease hands and work surfaces (or dough hook and bowl if you're lazy like me). I've never bought premade fondant so I don't have much to compare it with, but my MMF is stretchy and can be worked thin for flowers.