Sunshine Custard Frosting

• 4 egg yolks
• 2 tablespoons corn starch
• 1.5 cups granulated sugar
• 2 cups whole milk
• 1 teaspoon lemon zest
• 8 teaspoons butter, softened
• 1/4 cup lemon juice

1. In a medium mixing bowl, whisk together egg yolks, sugar and corn starch until well combined and frothy
2. In a saucepan over medium heat, heat the milk and lemon zest to just under boiling (200 degrees F if you have a thermometer). Slowly whisk in about 1/2 cup of the hot milk into the eggs. Then pour the eggs into the saucepan, whisking constantly. Keep the pan over medium heat (or medium low if your stovetop tends to run hot) and keep whisking until the temperature reaches 185 degrees F. (If you do not have a thermometer, you will see the mixture suddenly seize up into a paste).
3. Put the mixture in a bowl and cover with plastic wrap, pressing the plastic right onto the surface of the custard (this prevents a skin from forming). Refrigerate for at least 2 hours or until completely chilled.
4. Once the custard is cooled have your butter ready, put it in a large mixing bowl and start whipping it (ideally with a hand mixer or stand mixer -- you could do it by hand, but only if you have strong wrists!).
5. The butter should be soft, but not melted and cut into cubes of about a tablespoon each. Drop in one cube at a time and whip until incorporated, then add the next cube. Once you have a whipped in all the butter, add the lemon juice and a pinch of salt and whip to combine.
6. Your frosting is now ready to pipe or ice.

egg yolks, corn starch, sugar, milk, lemon zest, butter, lemon juice

Taken from food52.com/recipes/24597-sunshine-custard-frosting (may not work)