To prepare the semifreddo

1. Preheat the oven to 400 degrees.
2. Line a bread pan (9″x5″x3″) with plastic wrap or parchment paper, allowing an inch overhang on every side.
3. Place the peaches on a sheet pan with 1/4 cup of the sugar and salt. Toss to combine. Roast in the oven for 15 minutes or until the peaches have begun to release their juices and are tender. Allow to cool slightly, then puree the peaches and juices in a blender until smooth. Cool in the fridge while you continue to work.
4. In a double boiler, or in a pot with a glass bowl fitted on top (but not touching the water), whisk together the eggs and 1/4 cup of sugar. Continue to whisk, cooking gently over the simmering water until sugar is dissolved and the egg mixture registers 160 degrees on an instant read thermometer. This took me about 6 minutes.
5. Pour the eggs into the bowl of a stand mixture and, using the whisk attachment, beat until the mixture is pale, fluffy, and nearly tripled in size.
6. Meanwhile, in a separate bowl, beat the cream, final 1/4 cup of sugar, and vanilla until soft peaks form.
7. Gently stir 1/2 cup of the peach puree into the eggs. Fold 1/2 of the whipped cream into the eggs. Once combined, fold the remaining whipped cream into the eggs.
8. Spread about 1-1/4 cup of the mixture into the bottom of the prepared pan and then drizzle with 1/3 of the remaining peach puree. Repeat this process three more times, ending by smoothing out the final quarter of cream and egg mixture. Cover with plastic wrap and place in the freezer for 6 hours or overnight.
9. When ready to serve, remove from pan by pulling up on sides of the parchment paper and flip out onto a plate or serving platter. Slice as you would a loaf of bread and serve slices with warm blackberry compote and whipped cream, if desired.

To prepare the compote

1. Combine the blackberries, water, sugar, lemon, and mint in a small saucepan over medium heat. Cook for 10-15 minutes or until thick and bubbly. Remove the mint and stir in the vanilla. Allow to cool slightly before topping the semifreddo.