Preheat the oven to 325 degrees F. Line a regular-size cupcake pan with 18 cupcake liners.
Sift together the flour, baking powder, salt, and sugar. In the bowl of an electric stand mixer with a paddle attachment, add the sifted dry ingredients and mix on low speed for 30 seconds. Slowly add the oil to the mixture until fine crumbs are formed. Add the eggs, milk, raspberry extract, and pureed raspberries and mix on low speed for 1 minute. Stop and scrape the bowl and paddle, and then mix on medium speed for 2 minutes.
Fill the cupcake liners three-quarters full with batter and bake until baked through, about 20 minutes. Do not open the oven during this time. Cool cupcakes completely after baking.
Put the Champagne Buttercream Frosting into a pastry bag and cut 1/2-inch off the tip. Frost each cupcake in a circular motion until the top of the cupcake is completely covered and serve.
In the bowl of an electric stand mixer with a whisk attachment, whip the butter until creamed. Add the powdered sugar and champagne and mix until the ingredients are evenly incorporated and the frosting is smooth and creamy.
NotesThis recipe was provided by professional chefs and has been scaled down from a bulk recipe provided by a restaurant. The Food Network Kitchens chefs have not tested this recipe, in the proportions indicated, and therefore, we cannot make any representation as to the results.