Preheat oven to 350°F degrees. Line a standard cupcake pan with 8 paper liners.

In a large bowl or stand mixer, cream together butter and sugar until light and fluffy. Mix in egg and vanilla, followed by optional lemon extract, lemon juice and lemon zest. Scrape bowl and beater as needed. Mix in salt, baking powder and flour. Lastly, add sour cream, mixing until just combined and no streaks remain. 

Divide batter equally between prepared liners using a large cookie scoop. Bake for 18-20 minutes or until a toothpick inserted comes out clean. Cool in pan for several minutes, or until easy to handle. Transfer to a wire rack to cool completely. 

When cupcakes have cooled complately, prepare frosting. In a large bowl or stand mixer, beat together softened cream cheese and butter until smooth and fully combined. Add 1 cup of powdered sugar at a time until fully combined. Add *lemon curd. Mix until fully combined and desired consistency is reached. Transfer frosting to a piping bag fit with a jumbo round tip. Frost and decorate as desired. 

Store cupcakes in an airtight container at room temperature for up to several days or store chilled. 

If decorating with lemon curls; wrap thin sections of lemon peel around a straw or pencil, pinning into place for 30-60 minutes or until shape has set. Make curls and garnish cupcakes just prior to serving.