Place the egg yolks in the bowl of a stand mixer with the whisk attachment
Add the 1 tsp of Dijon mustard
Turn on the mixer and mix the egg yolk and Dijon for about 20-30 seconds
Start adding the olive oil in a steady stream. You want the egg and olive oil to "connect" and bind together and start to thicken.
Keep adding the olive oil until you have used 3/4 to one cup of olive oil.
Keep the machine on and slowly add the second oil- grapeseed or sunflower.
If the mayonnaise starts to get too thin add a little of olive oil and then continue with the second oil.
You can make this with only olive oil. It is still fabulous, just heavier.
I never measure the oils, I go by feel adding about half olive oil and half either sunflower or grapeseed oil.
Next, use a garlic press to add 3-6 cloves of garlic and mix into the mayonnaise.
Add Celtic salt and pepper.