Aioli

Mince and mash garlic to a paste with a pinch of salt using a large heavy knife. Whisk together yolk, lemon juice, and mustard in a bowl. Combine oils and add, a few drops at a time, to yolk mixture, whisking constantly, until all oil is incorporated and mixture is emulsified. (If mixture separates, stop adding oil and continue whisking until mixture comes together, then resume adding oil.)