Preheat your oven to 350°F (175°C). Line a 12-cup muffin tin with paper liners.
In a medium bowl, whisk together flour, baking powder, baking soda, and salt. Set aside.
In a large bowl, mix oil, granulated sugar, and brown sugar until smooth. Beat in the eggs one at a time. Add lemon juice, lemon zest, buttermilk, and vanilla extract. Mix until combined.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix.
Divide the batter evenly among the 12 cupcake liners, filling each about ⅔ full. Bake for 16–18 minutes or until a toothpick inserted into the center comes out clean. Cool completely.
In a large bowl, beat the softened butter until creamy. Gradually add powdered sugar, one cup at a time. Add lemonade concentrate and vanilla extract. Mix until fluffy. If desired, tint with food coloring.
Once cupcakes are completely cooled, frost using a piping bag or spoon. Garnish with lemon slices or sprinkles if desired.