Preheat your oven to 350 degrees Fahrenheit.
Sift together cake flour, baking powder and salt. Set aside.
Cream butter for about 3 minutes, scraping down sides of bowl occasionally.
Gradually add brown sugar, creaming after each addition. Set mixture aside.
Beat egg yolks until thick and lemon colored.
Add to the creamed mixture in thirds, beating thoroughly after each addition.
Blend milk and maple syrup together.
Beating only until smooth after each addition, alternately add the dry ingredients and liquids to the creamed mixture.
Beat only until smooth and fill cupcake liners using an ice cream scoop.
Bake for approximately 15 minutes or until a toothpick comes out clean.
Once cool, frost cupcakes.