That was a long time ago and I've been making it on and off for years.
Keep in mind it doesn't quite taste like store bought mayonnaise. It doesn't have the preservatives!
1 tbsp lemon juice
1/2 tspn salt
1/4 tspn white pepper
1 1/2 cups vegetable oil (I usually use olive oil for health benefits but veg tastes better)
You can either make this in a food processor or blender. Add egg, lemon juice, white pepper and process for 2 - 3 seconds. Leave machine running and slowly add oil. It should thicken within seconds.