In large bowl, beat butter with electric mixture on medium speed 30 seconds. Gradually add sugar, about 1/4 cup at a time, beating well after each addition. Beat 2 minutes longer. Add eggs, one at a time, beating well after each addition. Beat in vanilla. On low speed, alternatively add flour mixture, about 1/3 of mixture at a time, and yogurt, about 1/2 at a time, beating just until blended. In small bowl, toss peach with 1 tablespoon flour; fold into batter.