The next important thing to do is be sure to bring all of your ingredients to room temp. This is really important for the emulsification. To warm your egg you can place it in water for 3 mins, or leave it out. Its safe to do so until it fully reaches room temp.

Place the egg, 1/4 cup of olive oil, mustard powder, and salt in a blender. Do Not add the lemon, or if preferred lime yet, it's your very last step. Mix thoroughly

While the blender is running, very (and I mean so slow you start to yawn, and feel a nap approaching while doing so.) slowly drizzle in the remaining cup of olive oil. Yes, this is important to the process, so don't rush it, please. It's worth the results.

After you’ve added all the oil and the mixture has already fully emulsified, add lemon juice to your taste. Take it slow, as you can always add more. Stir gently with a spoon until incorporated.

Be sure to add your lemon juice last after your mayo has thickened up. It's believed that the acid in the lemon juice can mess with the emulsification process. The more lemon juice you add, the thinner the mixture will be.

If your mayo fails it's most likely due to the ingredients being too cold, or you poured too fast rushing the process, or added the lemon juice before your mayo emulsified properly. It's worth the patience, and you'll receive compliments for your delicious light mayo.

Here's a few tips on how to ensure your mayo doesn't fail. First, make sure you use light olive oil, not extra-virgin. EVOO is way too heavy.) You can also use a high-oleic safflower sunflower oil, and my personal favorite grape seed oil. The seeds used to make these oils contain more healthy monounsaturated fats and less polyunsaturated fats, almost identical to olive oil. The flavor of all four of these oils is very mild, so they're ideal for making mayo. I've experimented with other oils, and find people don't care for the taste of other oils like walnut, avocado etc.