Preheat oven to 350 degrees. Line standard muffin tins with paper liners. Sift together both flours, baking powder, salt, and 1 tablespoon cinnamon.
With an electric mixer on medium-high speed, cream butter and sugar until pale and fluffy. Add eggs, one at a time, beating until each is incorporated, scraping down sides of bowl as needed. Beat in vanilla. Reduce speed to low. Add flour mixture in three batches, alternating with two additions of milk, and beating until combined after each.
Divide batter evenly among lined cups, filling each three-quarters full. Bake, rotating tins halfway through, until a cake tester inserted in centers comes out clean, about 20 minutes. Transfer tins to wire racks to cool completely before removing cupcakes. Cupcakes can be stored up to 2 days at room temperature, or frozen up to 2 months, in airtight containers.
To finish, combine remaining 1/2 teaspoon cinnamon and 2 tablespoons sugar. Using a pastry bag fitted with a large plain tip (Ateco No. 809 or Wilton No. 1A), pipe frosting on each cupcake: Hold bag over cupcake with tip just above top, and squeeze to create a dome of frosting, then release pressure and pull up to form a peak. Using a small, fine sieve, dust peaks with cinnamon-sugar. Cupcakes are best eaten the day they are frosted; keep at room temperature until ready to serve.