Bake garlic on a small oven tray at 180C for 30 minutes, until very soft. Set aside to cool.
Squeeze garlic from the skins into a small food processor. Add egg yolks and a pinch of salt. Process until creamy. With motor running, add oil in a thin steady stream, until mixture is thick. Add lemon juice and pulse to combine.
Store in an airtight container in the refrigerator for up to 1 week.