In the bowl of a blender or (mini) food processor, place the granulated sugar and culinary lavender. Cover and blend or pulse just until the lavender disappears into the sugar.
Set the lavender sugar aside to use in the cupcakes and the glaze below.
Make the cupcakes
Preheat your oven to 325°F. Grease or line a standard 12-cup muffin tin and set it aside.
Place the flour, xanthan gum, cornstarch, baking powder, baking soda, and salt in a small bowl, and whisk to combine well. Set the bowl aside.
In the bowl of a stand mixer fitted with the paddle attachment, or a large bowl with a handheld mixer, place the butter, 1 cup of the lavender sugar, egg, egg white, and vanilla, and beat at medium-low speed to combine.
Increase the mixer speed to medium-high and beat until the mixture appears whipped (about 2 minutes).
To the large bowl with the butter mixture, add half the dry ingredients and beat lightly until just combined.
Add the buttermilk, and beat lightly, then the remaining dry ingredients, beating again until just combined.
Fill the prepared muffin cups 3/4 full of batter, and shake the pan back and forth to even out the batter in the cups.
Place the tin in the center of the preheated oven. Bake until the cupcakes are lightly golden brown around the edges and a toothpick inserted in the center comes out mostly clean (about 19 minutes).
Remove the tin from the oven and allow to cool at least 10 minutes in the pan. Transfer to a wire rack to cool completely.
Make the glaze.
In a medium-size bowl, place the confectioners’ sugar and add about 1 teaspoon of the milk. Mix until you have a very smooth, thick paste.
Add the remaining 1/4 cup of lavender sugar, and more milk by the drop, mixing well, until you have a very thickly pourable glaze.
Add the liquid slowly, because it’s much easier to thin the glaze than to thicken if once you’ve added too much liquid.
Add the optional blue and red gel food coloring, and mix until you have a purple glaze.
Glaze the cupcakes.
Dip the tops of the first cooled cupcake into the glaze, bobbing the top 3 times, and then slowly twisting the cupcake until it is upright.
Place on a sheet of parchment paper to set. Repeat with the remaining cupcakes.
If desired, sprinkle with a few lavender buds before the glaze is set.
Allow the cupcakes to set at room temperature and then serve.
Video
Notes
Originally published on the blog in 2012. In 2022, cupcake recipe updated and glaze recipe simplified; most text, video, and photos new.