Preheat oven to 350 degrees F and line a muffin pan with paper liners.
In a small bowl, sift together flour, baking powder, baking soda and salt.
In a separate bowl, whisk eggs and sugar until creamy. Add vegetable oil and whisk some more.
Add lemon juice and zest and mix.
Alternating with your dry ingredients and buttermilk, add slowly to wet ingredients and mix until all ingredients are thoroughly combined.
Add blueberries and carefully fold into the cake batter.
Fill lined muffin pan with cupcake batter, about 2/3 of the way. Bake for 15-17 minutes.
Allow to cool before topping with buttercream frosting.
To make the frosting, beat together butter, icing sugar and milk using an electric mixer. Start on slow speed and gradually increase to high.
Once the ingredients are well-mixed and smooth, add gel food coloring of each color and beat until completely tinted.
Scoop into a large piping bag with Wilton’s 1M icing tip attached. Frost each cupcake.
Top off each cupcake with one blueberry and serve. Enjoy!