1. Preheat the oven to 225°F and line two baking sheets with parchment paper. If desired, trace small circles on the parchment as guides, then turn the paper over.

2. Add the egg whites to a very clean mixing bowl and beat until foamy.

3. Add the cream of tartar and continue beating while gradually adding the granulated sugar, one spoonful at a time.

4. Beat until the meringue is glossy and holds stiff peaks, then mix in the vanilla extract and enough green gel food coloring to create a wreath-like shade.

5. Transfer the meringue to a piping bag fitted with a star tip and pipe 10 to 12 small wreaths onto the prepared baking sheets.

6. Bake for 1 hour, or until the meringues are dry to the touch and lift easily from the parchment.

7. Turn off the oven, crack the door open slightly, and let the meringues cool inside for 1 hour.

8. In a chilled bowl, whip the heavy cream with the powdered sugar until soft peaks form.

9. Spoon or pipe whipped cream into the center of each cooled meringue wreath.

10. Top with strawberries, raspberries, blueberries, and fresh mint leaves if desired.

11. Serve immediately after assembling for the best crisp texture.