Preheat oven to 350ºF. Place flattened grocery bag on top of cookie sheet.
Combine first four ingredients in a medium bowl. Beat at medium speed until soft peaks form, approximately three to four minutes. Gradually add sugar and beat until stiff.
Pour meringue onto the brown bag; form a circle that is about 10 inches in diameter and one-and-a-half to two-inches thick. Bake for 45 minutes.
Remove from oven and peel meringue off bag (it’s okay if it breaks into pieces). Place on a large serving platter. Allow to cool. When ready to serve, scoop ice cream on top of meringue layer, followed by the whipped cream. Sprinkle the strawberries and blueberries over the top and serve immediately.