Heat oven to 350°F. On clean surface, knead cookie dough and flour until well combined. Roll dough out to 1/4-inch thickness. Cut out ten 4-1/2-inch circles, rerolling scraps, and place on two baking sheets. Bake 15 minutes, or until golden brown. Transfer to wire rack and cool completely.
Trim tops of cupcakes. Place cupcakes, trimmed side down, in the center of each cookie, using frosting to secure. Fill in gap around base of cupcake with frosting. Divide remaining frosting among three bowls; tint to desired colors. Put assembled bonnets on a wire rack placed over a sheet of wax paper. Heat one bowl of frosting in the microwave for 5 to 10 seconds or until frosting is the consistency of slightly whipped cream. Slowly pour frosting over bonnets to cover completely. Repeat with remaining cupcakes and other colored frostings.
To decorate, cut marshmallows crosswise into thirds for flower petals and leaves. Arrange in decorative patterns over cupcakes. Place candy decors in centers of flowers.