We began this play dough birthday cake counting lesson last summer when E was two and a half. That is why she looks so young in these pictures. (I don't have a time machine that makes my kids younger again, but sometimes I wish I did!)
You just need play dough (ours is homemade), candles, and trinkets and beads for sprinkles and decorations! Poking the candles in the "cake" is great for fine motor practice. We would pick an age and a loved one and get their cake ready for them!
Counting while doing something physical, like adding candles to a cake, teaches one-to-one correspondence. One-to-one correspondence is the concept that one object (in this case, the candles) is represented by one number as we count. Rote counting, on the other hand, is simply counting verbally. Rote counting may hold no mathematical connection in a child's mind if they aren't also practicing one-to-one correspondence.