Directions:

1. To make the meringue base, heat the oven to 375 degrees F/190 degrees C. Line a half sheet-pan with parchment paper so the paper overlaps the long edges of the pan a little.

2. Place the egg whites in a mixing bowl and, using the whisk attachment of a stand mixer or hand mixer, beat on medium-high speeed for about 1 minute, until soft peaks form. Gradually add the sugar, about a tablespoon at a time and continuously beating, for about 5 minutes, until the mixture turns into a thick and glossy meringue. Turn the speed to low and add the vanilla extract, vinegar and cornstarch. Increase the speed to medium and beat until thoroughly combined, about 30 seconds.

3. Spoon the meringue onto the lined baking sheet and use a spatula to spread it out evenly into a rectangle that nearly takes up the whole pan. Place in the preheated oven and immediately lower the temperature to 350 degrees F/180 degrees C; the change in temperature helps create the crisp outside along with the gooey marshmallow-like inside. Bake for 28 - 32 minutes, until the meringue is pale beige in color and crusty on top. Remove from the oven and set aside in the pan until completely cool. The meringue will have puffed up in the oven but will deflate slightly when cooled. Cover gently with a clean kitchen towel and keep at room temperature until ready to use. (You can wait 8 hours or so, or use it right away.)

4. To make the filling, using a stand or hand mixer with the whisk attachment on medium-high speed, beat the cream in a large mixing bowl until very soft peaks form. Add the vanilla extract and confectioner?s sugar and whisk to incorporate.

5. Keeping the kitchen towel spread flat on top of the meringue, quickly but very carefully invert the meringue onto the work surface, so the meringue is now facing down on top of the kitchen towel. Lift the pan off and carefully peel away the parchment, then spread the meringue evening with two-thirds of the whipped cream. Arrange 1 pound, 2 ounces/500 g of the peach slices and 7 ounces/200 g of the blackberries evenly over the whipped cream, and sprinkle with 1/3 cup/40 g of the sliced almonds.

6. Starting with one of the long sides closest to you, and using the kitchen towel to assist, roll the meringue up and over, so that the edges come together to form a log. Gently pull away the kitchen towel as you roll, then slice the meringue onto a long tray or platter, seam-side-down. Don?t worry if the meringue loses its shape a bit or some of the fruit spills out; just hold your nerve and use your hands to pat it back into the shape of the log.

7. Spoon or pipe the remaining whipped cream down the length of the log. Top with the remaining fruit and almonds, dust with confectioner?s sugar, and serve.