Cookie baking reminds me of days gone by in our homeschooling life as well. Between helping their dad with tools in the garage and helping me bake cookies, my kids had a pretty hands on experience while learning fractions. As they both seem to have a pretty good handle on what a fraction is and how to handle it in the world of math, I would definitely encourage other homeschooling families to include this type of hands on lesson in their regular day. Public school kids can also benefit with a little after school brush up lesson while helping with dinner or dessert. Fractions are such an every day thing that knowing how to manipulate them can save a lot of time and money in the real world. Getting to know them in a fun way that comes with a sweet reward when the lesson's done is a great way to make sure the information sticks in young minds.
For younger munchkins, start small. Let them count how many parts make a whole with 1/4 cups, 1/3 cups, and 1/2 cups. If they have great motor skills, turn them loose on the measuring spoons as well! As they grow, let them measure for you. Have them predict the number of 1/4 cups they will need when a recipe calls for 2 3/4 cups of something. Then reinforce how those cups need to be level and help them count out to the right amount. Older math whizzes get great fraction practice by doubling recipes, or by halving them. Multiplication and division can be included as well with the creative application of large batch planning. If you don't have a large crowd to feed, just keep the plans on paper.
So this year, spend some time with your kids in the kitchen during the holiday season. It's a wonderful way to get some extra fun time with them while polishing a very necessary math skill!