1Heat oven to 350°F. Place paper baking cup in each of 12 regular-size muffin cups.
2In large bowl, beat butter and sugar with electric mixer on medium speed until light and fluffy. Add egg and banana, beating until well mixed. Beat in yogurt. Stir in oats, dried strawberries and walnuts. Divide mixture evenly among muffin cups.
3Bake about 25 minutes or until tops are golden brown. Cool on rack 15 minutes.