How to veganize and improve this cake recipe?

To make it vegan is simple:

• Replace the milk with any other kind of milk (soy, rice, hemp, etc.)
• Replace butter with some kind of margarine (I recommend Earth Balance, but just pick anything that doesn't have trans fats)
• Replace eggs with either commercial egg replacer, or apple sauce

As for making it moister, I have no idea.

I would replace the butter with a butter-flavored vegetable shortening (like Brendan said, it's best to avoid trans fats). However, butter is only about 80% fat and 20% water, so you may want to slightly reduce the amount of fat you're replacing it with and add a bit of extra liquid.

For the egg, you can see the answers to this question: With what can I replace eggs?

In addition to egg replacer, making a flax seed egg is a fairly common way to vegan-ize a baking recipe that uses eggs.

You can make it moister by replacing the eggs with apple sauce or soy yogurt (about 1/4 c per egg) and replace the butter with Earth Balance Margarine and the milk with any non-dairy milk.

Because this cake needs to be fairly firm though, I wouldn't mess with replacing the eggs and I would just use a recipe that was vegan to begin with. The cake recipes from here http://www.pakupaku.info/index.html have the best texture for things like this from the recipes I've tried.

When you're replacing this much egg in a recipe you need to do some experimenting to get things just right, and I'm too lazy to do all that so I just find a vegan recipe and go from there.

If it's not moist enough for you I would add a flavor syrup before frosting it. Just brush the whole cake with a simple syrup in a flavor you like. I usually add a small amount of margarine in addition to the flavor ingredient. Brush it on while the cake and the syrup are still a little warm.

Mr Shiny and New you have a real problem here to replace 4 eggs in a 3 cup flour mix. I have successfully made a cake with half the flour and replaced the eggs with 1 teaspoon of bicarbonate soda in with baking powder and 1 tablespoon of lemon juice or vinegar and if this was unsuccessful my next trial would be to use the egg replacer with the vinegar and bi-carbonate of soda together in the cake. The amount of flour is the reference point requiring the balance of ingredients for a normal cake to be produced. My cupcake recipe uses 1 1/2 cups of self raising flour and 1 tablespoon of lemon juice, my mango cake recipe is the same flour but mango fruit and juice replaces the acid and the bicarbonate soda (same amount) works to give the cake lift even though there is a lot of dried fruit in the mix. The recipe is on the net and the only thing I do not add is the eggs, all other ingredients are the same. My next option would be to halve the recipe and make an egg replacement as I have suggested. I would also use any of the other advice above myself as it has worked for me in baking without eggs in the past.

Baking a cake is more chemistry than cooking, all about proportions.

The success rate of making cake recipes vegan depends highly on the suitability of the recipe for conversion. Dairy components are not too hard to replace, good soya milk will usually replace regular milk without issue providing curdling issues are not too great and butter can usually be replaced with a decent vegan block margarine, and there are decent vegan soft margarines about. Eggs are always tricky and have to be replaced with something suitable, one size does not fit all, it very much depends upon the recipe what is the best method.

Eggs add air, they bind, alter the shelf-life and effect the moistness of the cake. If there are a lot of eggs in a recipe they can be making up a strategic part of the dough in a texture capacity as well as altering the taste too. The strategy to adopt is to work out what primary purpose the eggs are serving in the recipe and replace them. In fruit cakes where the egg is binding, a date syrup or mashed banana can work with a little more raising agent. But this significantly effects the flavour obviously, so is usually reserved for rich fruit cakes where the flavours sit comfortably. In sponges, soya flour and raising agents (or a cake-specific egg substitute which is usually soya protein isolate and raising agents) can aid softness and binding. When there are a lot of eggs the recipe will usually be too hard to adapt.

Your recipe looks about 2:1:1 -- flour:fat:eggs, which would usually be suitable for a cake egg substitute. Particularly given the plain flavouring of the cake, the egg will be contributing flavour there as will the butter substantially. A hard recipe to make acceptable.

• 3 cups (470g) all-purpose flour
• 2 tsp baking powder
• 1 1/2 tsp salt
• 16 tbs (250g) unsalted butter --> coconut oil (gives a better flavor/texture than margarin)
• 2 cups (500g) sugar --> turbinado sugar or sugar in the raw. (Bone Char free sugar)
• 4 eggs --> Flax Seed (perfect egg replacement for baking, perfect cake texture)
• 1 1/3 cups milk --> Almond milk or Rice Milk
• 1 1/2 tsp vanilla

Most mainstream sugars on the market are bleached with bone char made from cow bones. You will need to find a vegan sugar. Sugar made from evaporated cane juice is generally ok. There is a good list of companies here: http://www.veganproducts.org/sugar.html#Brands

I have found that Flax seed is the very best egg replacement in vegan baking recipes. The texture of baked goods comes out exactly the same as recipes using eggs. The cake crumb is perfect and holds together wonderfully. There is a great article on using flax seeds as egg replacements here: http://www.veganbaking.net/recipes/egg-replacers/flax-seed-egg-replacer

Another alternative to eggs would be to use tapioca flour, you can mix 1 Tbsp with 2 Tbsp water per egg.

Potato flour- a small amount can add moisture to the cake