For Raspberry Pavlova:
1. Preheat oven to 250 degrees. Trace a 10-inch-diameter circle on a piece of parchment with a pencil. Trace a 5 1/2-inch-diameter circle in center of larger circle. Place on a baking sheet, tracing-side down.

2. Whisk egg whites on medium-high speed until soft peaks form. Gradually add 1 1/2 cups sugar, beating until stiff peaks form. Beat in vinegar, cornstarch, vanilla, and raspberry flavoring.

3. Transfer mixture to a large piping bag fitted with a large plain tip (such as Ateco #808). Pipe 10 evenly spaced mounds (each about 2 1/4 inches in diameter and 2 inches high) onto parchment in a circle, using traced ring as a guide.

4. With the back of a spoon, create a hollow in each mound. Bake until ring easily lifts off parchment, about 1 hour, 10 minutes. Turn off heat; let stand in oven 1 hour.

For Raspberry Curd:
1. Set out two bowls, one with the butter in it and one with a fine mesh sieve over it.

2. Place the frozen raspberries, the zest and the lemon juice in a small pot. Cook on medium to low heat until the raspberries soften and burst and it’s mostly liquid.

3. Press the raspberry mix through the fine mesh sieve to remove the seeds and zest, scraping the bottom of the sieve. You should have ¾ cup raspberry lemon juice. Discard the seeds and rinse the sieve and pat dry, and set it over the bowl with the butter in it.

4. Return the raspberry juice to the pot and add the sugar and stir. The mix should have cooled quite a bit by now, if it’s hot, wait a bit. Whisk in the eggs (and starch if using) then return the pot to the stove, cooking at medium heat and whisking until the curd is thick at the bottom and covers the back of a wooden spoon or rubber spatula.

5. Pour the curd through the sieve and press to get as much curd out as possible, scraping the bottom of the sieve. Stir the curd and the butter until the butter is fully melted and you have a shiny, smooth curd. Transfer to a mason jar or Pyrex glass dish and store in the fridge. The curd will become more tart-tasting and stronger in flavor as it chills.

For Whipped Cream:
1. Put the bowl of a standing mixer or a large mixing bowl (glass or metal preferred) into the refrigerator to chill for at least 15-30 minutes (or longer).

2. Add whipping cream, powdered sugar and vanilla extract to the chilled bowl of a standing mixer (or chilled mixing bowl).

3. Use the wire whisk attachment to a standing mixer, or a hand-held mixer, and beat the ingredients together, starting on low speed and increasing to high slowly as it begins to firm up.

4. Beat for 60-90 seconds until stiff peaks form. Stopping once halfway through to scrape down the sides of the bowl.

5. Transfer mixture to a piping bag or store in a Pyrex glass bowl and place in the fridge if not serving the pavlova right away.

Assembly
1. To serve, divide raspberry curd and whipped cream evenly among hollows in pavlovas.

2. Garnish with raspberries, blackberries, and fresh mint.