Heat oven to 350°F. In medium bowl, place 1/3 cup of the cookie dough and 2 teaspoons of the oil. Cover; refrigerate. Let remaining cookie dough stand at room temperature 10 minutes to soften.
Meanwhile, place Reynolds® StayBrite® Baking Cup in each of 10 regular-size muffin cups. In small bowl, mash 1 banana (1/3 cup); set aside. Chop remaining 3 bananas into 1/4- to 1/2-inch pieces (1 cup). Place in medium bowl; set aside.
In large bowl, break up softened cookie dough. Beat with electric mixer on low speed 30 seconds. Add remaining 2 tablespoons oil, the egg and mashed banana. Beat on low speed 1 minute, scraping bowl as needed. Add 1/2 cup of the flour, the baking powder and 1/8 teaspoon salt. Beat on low speed 30 seconds, scraping bowl as needed. Beat on medium speed 1 minute. Gently stir in chopped banana. Divide batter evenly among muffin cups (cups will be full).
Remove cookie dough and oil from refrigerator. Add remaining 1/4 cup flour and the sugar. Mix with fork 1 to 2 minutes or until crumbly. Spoon 1 rounded tablespoon crumb mixture on top of each muffin; press in lightly.
Bake 25 to 30 minutes or until toothpick inserted in center comes out clean and tops are golden brown. Cool 10 minutes; remove from pan to cooling rack. Cool 20 minutes. Serve warm or cool. Store covered.