Well I couldn't put this down over Christmas after receiving it as a present! I would say that this game has two parts:
1) A detailed cook book
The cookbook offers a wide variety of wonderful recipes you can try and cook yourself at home. In essence I suppose its just Jamie's recipe book but on the DS. This is great although I think it would have been better again if Jamie had talked you through each recipe as with Can't Decide What to Eat. Sadly this is not the case. However, it does offer you the opportunity to select items you need for each recipe to create a shopping list.... though not sure taking your DS around the supermarket would be that practical!
It's the minigames that are the real fun in this game. You can actually prepare ingredients and create your own culinary delights in the Test Kitchen area and then save each recipe. You can battle against the clock to mini challenges Jamie sets you, such a cook a fried egg.... tip here being you need to forward time to get the egg to cook in time by pressing the X button.... I spent a while trying to figure this out! Also you are given the opportunity to go through set tutorials where you are taught how to make certain recipes.
All in all a very fun little game. I would recommend it.