For the cake: Preheat the oven to 350 degrees F and grease a 9-by 13-inch baking dish.
Add the flour, granulated sugar, baking powder and salt to the bowl of a stand mixer and mix on low speed to combine.
Next, slowly add in the butter slices and allow to mix until the flour resembles coarse crumbs.
While the butter mixes, in a separate bowl whisk together the eggs, pink lemonade, milk, lemon extract and vanilla extract.
With the mixer still on low speed, add the egg mixture in three batches, allowing the liquid to combine into the dry ingredients until fully incorporated. If desired, stir in a few drops of pink or red food coloring to create a light pink color.
Spread the batter evenly into the prepared pan and bake until a toothpick inserted into the center comes out mostly clean with a few crumbs, 30 to 35 minutes. Cool in the pan on a wire rack until room temperature. While cooling, prepare the frosting.
For the frosting: Combine the butter and salt in the stand mixer on low speed. Slowly add the confectioners' sugar in small amounts until all is added, and then turn the speed to medium-high to combine. Add the pink lemonade concentrate and lemon extract and mix until fluffy. Add in the food coloring at this point if desired.
Once the cake is fully cooled, ice with the frosting and decorate with lemon slices and straws, if desired.