If you've made homemade mayonnaise and find that it's too thin or runny, there are several ways to thicken it. Here are some methods you can try:
Egg yolk: The primary ingredient in mayonnaise is egg yolk, and adding an extra yolk can help thicken it. Beat another egg yolk in a separate bowl and slowly whisk it into the runny mayonnaise until you achieve the desired consistency.
Mustard: Mustard is an emulsifier, just like egg yolk, and can help stabilize and thicken mayonnaise. Add a small amount of mustard to your runny mayonnaise and whisk thoroughly until it thickens.
Lemon juice or vinegar: Acidic ingredients like lemon juice or vinegar can help thicken mayonnaise by providing additional emulsification. Start by adding a small amount, about a teaspoon at a time, and whisk it in. Taste as you go to avoid making the mayonnaise too tangy.
Olive oil: If you used a lighter oil like vegetable oil when making the mayonnaise, you can try adding a drizzle of extra virgin olive oil. Olive oil is thicker and will help bind the ingredients together.
Cornstarch or arrowroot powder: Mix a small amount of cornstarch or arrowroot powder with water to create a slurry, and then gently heat it in a saucepan until it thickens. Let it cool before slowly whisking it into the mayonnaise.
Blender or food processor: If your mayonnaise isn't emulsifying properly during the initial preparation, you can try blending it again. Add a tablespoon of water and blend until it thickens and becomes creamy.
Remember that some trial and error might be necessary, so add the thickening agents gradually to avoid over-thickening the mayonnaise. Additionally, keep in mind that the consistency of mayonnaise can vary depending on the recipe and the ingredients used. If the mayonnaise is still too thin after trying these methods, you may need to start over and adjust the ratio of oil to egg yolk in your recipe.