This achievement simply requires that you bake 5 chocolate puddings. In order to be able to bake, you must first have an oven. Purchase one from the Home Store if you do not. Chocolate pudding does not unlock until a few levels in. Once you are able to buy one, click on the oven with a free Sim and select the pudding to start baking. It will take 2 hours to complete, regardless of the type of oven your are using. Once it is finished baking, click on it to collect it. Repeat four more times. This does not need to be done with a single Sim or in a single oven.