In large bowl, beat 1/2 cup butter with electric mixer on medium speed 30 seconds. Gradually add granulated sugar, about 1/4 cup at a time, beating well after each addition, scraping bowl occasionally. Beat 2 minutes longer. Beat in 1 teaspoon maple flavor and the eggs. On low speed, alternately add flour mixture, about one-third at a time, and 3/4 cup milk, about half at a time, beating just until blended.