These cakes are dedicated to my friends Shy and Dukasha and should've been finished to their birthdays, however, due to various problems including real-life ones I wasn't able to do it in time However, I'd say it's never too late to enjoy a cake

They were cloned from 'London's famous birthday cake' and, like that cake, a sim who is growing up to another age group can use 'Blow Out Candles' on them.
In addition, sim of any age except toddler can use 'Celebrate - Blow Out Candles' to make a celebration anytime, not only when you have a suitable sim It works exactly the same as the standard 'Blow Out Candles' - sims gather and watch, active sim blows out the candles, cake becomes edible after it - except that active sim doesn't age.

The slices are animated correctly - they disappear when sim eats them.

Dukasha's cake has some more changes from the standard cake - it's square, has 8 slices instead of 6 (and 16 servings instead of 12) and has non-symmetrical texture - textures for all 8 slices are completely different, and slices grabbed on plates have textures corresponding to current slice in cake (i.e. 1st and 2nd grabbed plate have textures of 8th slice, 3rd and 4th have textures of 7th slice, etc.)

Cakes were created in base game and should work with all addons. Known bug with Open for Business: cakes cannot be placed in food display refrigerator, and even if they can be placed with one of Numenor's patches, they can't be restocked. As Shy explained, the problem is that food display accepts items of certain GUIDs or certain categories only; changing cakes to category Food will take quite a lot of work, the only other way to fix is to change bhavs in food display - I certainly can't do that because I have base game only.

As the standard cake, these cakes can be found under Miscellaneous/Party.

Technical details.
Cakes consist from big number of subsets - plate, N slices (6 for Shy's cake, 8 for Dukasha's cake), and 4 candle subsets for different ages.
I didn't altered candles.
Plates are made recolorable - each cake includes 2 recolors for plates, 'solid' and glass.
Slices aren't recolorable.
Mesh geometry for Shy's cake:
- plate - 108 faces, 110 vertices
- each of 6 slices - 254 faces, 374 vertices
- all candles - 1188 faces, 1620 vertices
Shy's cake piece is animated using morphs. Piece geometry:
- slice - 290 faces, 393 vertices
Mesh geometry for Dukasha's cake:
- plate - 12 faces, 24 vertices
- each of 8 slices - 148 faces, 140 vertices
- all candles - 1188 faces, 1620 vertices
Dukasha's cake piece is animated using ChangeMaterial. Piece geometry:
- slice - 81 faces, 79 vertices
- slice_half - 73 faces, 75 vertices
All meshes were created in 3dsmax and imported using smd plugin.
Actually, these cakes were 90%-finished a while ago, so they are ways simpler than my later objects :o

Thanks.
To skankyboy, for the smd plugin.
To Peter Jones, for PJSE plugins.
To Shy, for checking what's going on in OfB.

Policy.
Since plates are recolorable, feel free to recolor them. For cloning, ask my permission first. (I certainly wouldn't give permission if object is expected to be used as donation or pay item.)