Separate the egg whites from the yolks. Keep the whites in the fridge for an egg white omelet
Pour 2 teaspoons of lemon juice OR vinegar into the bowl with the egg yolks and whisk them until well combined
Slowly, a few drops of the oil at a time into the bowl while whisking constantly. Keep adding drops until the mayonnaise has started to thicken, then you can pour the oil in a slow and steady stream. If the oil starts to build up at all, stop pouring and whisk the mayonnaise briskly until the oil has incorporated.
Taste the mayonnaise, if you like a tangier mayo you may add the last teaspoon of lemon juice OR vinegar. If the mayonnaise starts looking too thick add about a teaspoon of water at a time until you get to the consistency you're looking for.
Once all the oil has been mixed in, the mayonnaise should be thick and fluffy, with your whisk forming ribbons through the mixture. Season it carefully with the salt and paprika, if desired.
Homemade mayonnaise can be stored in your fridge for up to one week in an air tight container. Glass containers are recommended over plastic.