You can buy cake pans in the shape of the number 7 and the number 5 – check your local craft store or you can find the pans online.
If you don’t want to spend the money on cake pans that you’ll only use once, you can cut ordinary cakes to the proper shape.
This handy diagram on the left shows you exactly how you’ll need to cut the cakes to get the right shapes.
To make the number 7, you’ll need to use a 6″ square cake.
For the number 5, you’ll use a 6″ round cake and a 6″ loaf cake. Be sure to put an empty can inside the round cake to make the center hole.
If you don’t have 6″ pans, it should work just as well using the more standard 9″ pans.
Since you’ll be making 2 big cakes, be sure you have a large enough surface to place them on side by side.
Some bakers recommend freezing the cakes before cutting them into the shapes, as the cakes will be easier to cut then.
Don’t forget to crumb coat the cut cakes before putting your final layer of icing on so that you don’t get crumbs all over your cake!
After you’ve cut the cakes to the proper shape you can then decorate them however you’d like.
Here are a few decorated 75th birthday cakes for inspiration: