Preheat oven to 350 degrees F. Line a 6-cup muffin tin with cupcake liners. Set aside.
Whip butter at medium speed with electric mixer. Add sugar and mix until well combine and light in color. Add egg, milk and Adams lemon extract.
With mixer on lowest speed, add flour and baking powder. Mix just until combined but batter is smooth, scraping down sides once.
Divide batter evenly among muffins wells and bake for 20 - 23 minutes or until toothpick inserted in center comes out clean. Remove from oven and cupcake pan to cooling rack.
Once completely cool, frost with lemon buttercream. Garnish with candied lemon wedges.
Prepare lemon buttercream:
In a mixing bowl, beat butter until fluffy. Add lemon juice and zest. Gradually add confectioners' sugar, scraping down sides. Add milk. You may need more milk depending on consistency. You want to be able to spread it on the cupcakes.
Notes
To make candied lemon:Slice lemon paper thin, a mandoline works well for this task. In a saucepan combine 1 cup of water and 1 cup of Dixie Crystals sugar. Bring mixture to a boil and add lemon slices. Reduce heat and simmer until slices are translucent. Be patient, this could take 30 minutes or longer, depending on the thickness of the slices. Remove to a cooling rack and let dry overnight. They will not dry completely but will be firm.