Vanilla extract can add extra richness of flavor to many baked goods. Unfortunately, there is no single ingredient that can successfully replace vanilla extract in all its uses. The best substitution for this common ingredient depends on the recipe in which you want to replace the vanilla extract. In some recipes, such as vanilla cookies, the vanilla flavor is absolutely vital, and you should replace vanilla extract with another vanilla product. In other recipes, such as pancakes or banana bread, you can replace vanilla extract with non-vanilla-flavored ingredients.
Determine the exact amount of vanilla extract in the recipe you wish to make. This amount is important regardless of which substitute you use, as it will help you determine how much of the substitute to add to your recipe.
If your recipe calls for 3/4 tsp. of vanilla extract, replace the extract with vanilla sugar if the vanilla flavor is vitally important to the recipe. Use 1 tbsp. vanilla sugar for each 1/4 tsp. vanilla extract in the original recipe. So you would use 3 tbsp. vanilla sugar to replace the 3/4 tsp. vanilla extract in the recipe. Reduce the amount of granulated sugar in the recipe accordingly, if possible, as vanilla extract adds only flavor rather than sweetness. In this example, you would reduce the amount of sugar in the recipe by 3 tbsp. Add the vanilla sugar to the other sugar in the recipe (or to the dry ingredients) rather than mixing it with the wet ingredients.
Substitute another flavorful liquid for vanilla extract if you do not have vanilla sugar or if the vanilla flavor is not vital to the recipe. Some options include maple syrup, triple sec, almond extract and rum. Select the option that you think would taste best with the recipe you are making. If you do not think almond flavor would work well with the recipe, try rum or framboise instead. Use an equal amount of the flavoring of your choice as the vanilla extract in the original recipe. Add this ingredient to the recipe in the same way as you would have added the vanilla.
Continue making the recipe as normal. You do not need to make any substitutions or changes to the recipe other than those already mentioned.
Maple syrup works well as a replacement for vanilla extract in many recipes, and runs less risk of tasting wrong with the recipe than almond extract, framboise or other distinctly flavored items. If you are not confident of your ability to decide which would go best with your recipe, use maple syrup.
References and ResourcesCooksUnited.co.uk: Vanilla Sugar
Diana's Desserts: Ingredient Substitution Chart
OChef: Is There a Simple Substitute for Vanilla?
OChef: Substitute for Vanilla Extract --- Take II