One of the nice things about working in a studio with other potters is getting to use their stuff. I'm using Ronnie's butter dish template here.
Start with a slab and trace out as many butter dishes as will fit.
Smooth off the edges with a sponge, and apply any decoration. I used a leaf from the yard in the picture above. Sometimes I just decorate the edges of the dish with some texture.
Place the flat butter dish on the foam textured side up. Carefully position the wood block in the indention made by the template from the first step.
Push down into the foam. This causes the edges to curve upward around the block.
These butter dishes are done and ready to dry.