11⁄2 cups vegetable oil or mild extra-virgin olive oil (or a combination), divided.
How to make
Easy Homemade mayonnaise
Place a medium glass or metal bowl in the freezer to chill for 10 minutes.
Whisk together the egg yolks, lemon juice, vinegar, mustard, and salt in the chilled bowl. Whisk until blended and bright yellow, about 30 seconds.
Whisking constantly, add 1⁄2 cup of the oil a few drops at a time to the yolk mixture, taking about 4 minutes to do so. Add the remaining 1 cup of oil in a very slow, very thin, steady stream, whisking constantly until the mayonnaise is thick and lighter in color, 8 to 15 minutes, depending on your fortitude. (Putting the oil in a squeeze bottle with a small opening helps control the flow.)
Cover and let sit at room temperature for 1 hour, then refrigerate for up to 1 week.