What do you use to stack cakes like this in the picture below? Are they cake dummies? Can you use foam core? Styrafoam rounds from the craft store? If so, how do you support them so they will hold up the weight of the cake... any help would be appreciated. thanks

Cake dummies are strong enough to stand on, so they will definitely support the weight of a cake. (No pegs are required inside the dummy, however, you can use skewers to prevent sliding during transport.)

When using in between tiers, support the dummy the same way you would for real cake with a support system below the dummy making sure to use a plate or corrugated cardboard under the dummy to prevent the styrofoam from being pierced.

Thanks!!!