Egg Yolk Sauce

0 Prepare the Yolks: Separate the egg yolks from the whites (reserve the whites for another recipe if you would like) and place the yolks in a medium sized heatproof bowl.
1 Cook the Yolks: Fill a saucepan ⅓ of the way up with water and bring to a gentle simmer. Lower the heat to medium-low and set the bowl of eggs over the simmering water, making sure the bottom does not touch the water. Gently mix the yolks with a spoon or silicone spatula, rubbing them against the sides of the bowl, for about 90 seconds until jammy and slightly thickened. Remove from heat.
2 Finish the Yolks: Add the butter to the warm yolks and stir until fully melted and smooth. Season with flaky salt to taste.
3 Assemble the Toast: Rub the garlic slice across the warm toast. Spread the jammy yolks on top and finish with lemon zest, chives, more flaky salt, and black pepper.