Needing a little help...
1. When I use MMF, it tends to crack. What am I doing wrong? Letting it sit too long before using it?
2. What's the best way to attach MMF accents to the buttercream frosting on the cake? Water, piping gel....?
Add shortening or glycerin. Sounds like it's drying out. You don"t want to add water just use some buttercream or royal icing.
Yup, sounds like your MMF is drying out or is too dry to begin with. You want it to feel like satiny soft dough. If it's cracking add crisco, if it's sticking add PS. As for the accents...more BC will do the trick.
Yup- I agree, sounds like it's just too dry.
Assuming you're making it, try adding less PS next time. I stop when it seems a *little* too soft but will just barely hold it's shape. After wrapping it well and letting it sit for 12 hours it has cooled and firmed and is the perfect, elastic texture.
From my experience I'd much rather have it end up on the soft side because kneading in more PS is much better than loading it with Crisco. Also, if your recipe has no corn syrup, adding a bit of that may help too! HTH