I think investing in a copy of The Cake Bible would be a good idea for you. You'll get extremely detailed instruction and a variety of recipes for cakes, icings, and fillings in varying difficulties. At the back of the book, you'll find instructions and a few different recipes for wedding cakes.
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The instruction in this book just can't be beat. You will learn so much.
At 10, most budding cooks are into pastry (AKA dessert type dishes). Given that you have a new kitchen toy - a KitchenAid - I would give a gift of time and play. Buy her The Cake Bible, a classic and pair it with some shelf stable cake baking ingredients/pans/bowls as needed and "coupons" redeemable for the required ingredients and the parental assistance time to make 2 cakes of her choosing from the book. Kids really just want time with their attentive parents, so you can hit all the bases with one gift.
The Cake Bible by Rose Levy Beranbaum. Probably one of the best cookbooks published of all time. The great part is that she is VERY easy to contact and will respond to anyone that needs help if you go to her website.
The Cake Bible is where I would (and did) start.
The cheesecake in The cake bible is the best cheesecake I have ever eaten. As for advice (other than just using it) is make sure you do NOT open the oven. ever. I believe the recipe in TCB says to cook it, turn off the oven, then wait an hour before removing it. Really waiting a couple hours till it is room temperature seems to work best for me. I have never had it crack if I do this, every time I have opened it though, it has cracked.
Recommendation: https://www.amazon.com/Cake-Bible-Rose-Levy-Beranbaum/dp/0688044026/ref=sr_1_1?ie=UTF8&qid=1522036236&sr=8-1&keywords=the+cake+bible
Seriously, couple bucks, clear instructions, AWESOME cakes.
I really like The Cake Bible and the Bread Bible for a similarly methodical approach to baking. Rose Levy Beranbaum breaks down every ingredient, every substitution, every process, and brings a scientific curiosity to all her recipes, with stellar, replicable results.
luster and sparkle dust for sure, maybe gold leaf if you want to be fancy! (http://www.fancyflours.com/luster-dust-aztec-gold.html, http://www.fancyflours.com/Detailed%20Embellishments/Edible%20Gold%20%26%20Silver%20Leaf) that can get pricey and is a must to get fancy with your decorating. digital scale if she doesn't have one. this cookbook (http://www.amazon.com/Cake-Bible-Rose-Levy-Beranbaum/dp/0688044026/ref=pd_sim_b_1 -- the gold standard) or this one (http://www.amazon.com/Baked-Frontiers-Baking-Matt-Lewis/dp/1584797215 -- hott). fancy linings? http://www.fancyflours.com/Inspired%20Baking/Baking%20Cups
Pretty much anything in those book is awesome: http://www.amazon.com/Cake-Bible-Rose-Levy-Beranbaum/dp/0688044026