In a small saucepan, combine the sugar and lemon zest. Use your fingertips to massage the zest into the sugar until the mixture is fragrant and looks like wet sand.

Add the egg yolks and whole egg to the saucepan and whisk vigorously until the mixture is very pale and thick, about 2 minutes.

Slowly stream in the lemon juice, whisking constantly until the mixture is smooth. Whisk in the salt.

Place the saucepan over medium-low heat and cook, whisking constantly, until the curd turns opaque yellow and is thick enough to coat the back of a spoon, about 7-10 minutes. Immediately remove the saucepan from the heat.

Whisk in the butter, one piece at a time, waiting for each piece to disappear into the curd before adding the next. Whisk in the vanilla.

Transfer the curd to a heat-safe bowl and press a piece of plastic wrap directly on top of it to prevent a skin from forming. Refrigerate until the curd is cold and set, at least 3 hours. Not all of the lemon curd will be needed for the tea cakes. Leftover curd can be kept in an airtight container in the refrigerator.

Preheat the oven to 350 F. Grease a mini loaf pan with cooking spray.

Whisk together the flour, baking powder, and salt in a medium bowl. Set aside.

In a small bowl, combine the granulated sugar and lemon zest. Use your fingertips to massage the zest into the sugar until the mixture is fragrant and looks like wet sand.

Combine the oil, butter, and sugars together in a large bowl and beat until light and fluffy, about 2 minutes.

Add the buttermilk, vanilla extract, and eggs to the sugar mixture. Beat on low speed until combined.

Add the flour mixture and beat on medium high speed until combined.

Transfer the batter to the prepared mini loaf pan, filling each cup about ¾ full.

Bake the loaves for 24-28 minutes or until a toothpick inserted into the center comes out clean.

Let cool for 5 minutes in the pan before transferring to a wire rack to cool completely.

Combine the powdered sugar, lemon juice, and melted butter in a medium bowl and whisk until smooth.

Transfer ½ cup of the lemon curd to a piping bag fitted with a bismarck piping tip or a medium round piping tip.

Insert the piping tip into the top center of the tea cake and pipe the lemon curd into it. Use a butter knife or offset spatula to smooth the top of the tea cake.

Dip the tops of the tea cakes into the glaze. If desired, gently press a small Mickey sprinkle onto the top of the tea cake. Let the glaze harden for 5 minutes before serving.