I was actually wondering the same thing. I just did a quick google search and came up with this.
Evaporated Milk
Evaporated milk is just 2 servings of milk in 1 serving of liquid.
So to get evaporated milk use twice as much instant dry soy milk powder to one serving of milk, or take ready made soy milk (with only soy beans and water on the label) and use that in place of water for mixing one serving of of instant dry soy milk powder.
Or
Sweetened Condensed 'Milk and Evaporated 'Milk
Condensed Soymilk or Rice Milk I (Quick Method)
Prepare 2 cups soymilk or rice milk made from powdered mix, using triple the powder called for.
Add 3/4 cup sugar or equivalent.
Cook over medium-low heat, stirring constantly, until sugar is dissolved.
Add vanilla to taste, and a pinch of salt.
Cool.
Store in jar in fridge.
For Evaporated 'Milk: Use only double the powder. Omit sugar.
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Condensed Soymilk or Rice Milk II (Slow-Cook Method)
Put 3 cups liquid soymilk or rice milk in a saucepan.
Add 1/2 cup sugar or equivalent.
Cook over medium-low heat, stirring constantly, until volume is reduced to 1 cup.
Add vanilla to taste, and a pinch of salt.
Cool.
Store in jar in fridge.
For Evaporated 'Milk: Cook until volume is reduced to 1 & 1/2 cups. Omit sugar.
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Condensed Soymilk or Rice Milk III (Semi-quick Method)
Put in blender:
1 cup powdered soymilk or rice milk -- do not pack down!
3 Tbsp melted margarine
2/3 cup sugar
1 tsp vanilla extract
Pinch of salt
1 cup boiling water
Blend together until well mixed.
Cool.
Store in jar in fridge.
For Evaporated 'Milk: Omit sugar, vanilla, margarine, and salt. Use 1 & 1/2 cups water.