In a mixer with a whisk attachment, whisk the cream into medium peaks. Add 1 cup of the sugar to the cream and continue to whisk until stiff peaks form. Turn the cream out into a large bowl. Clean the bowl and whisk attachment. Add the egg yolks and the remaining 1 cup sugar. Whisk until the yolks are pale yellow and tripled in volume. Add the yolks to the whipped cream. Add the almond or vanilla extract and begin to fold the yolks into the cream. Add the pistachios and turn the mixture out into a glass serving dish. Freeze overnight. To serve: Cut the semifreddo into desired size pieces. Place individual pieces in a serving bowl and top with berries and chocolate sauce. Garnish with powdered sugar and a sprig of mint.
Consumption of raw or undercooked eggs, shellfish and meat may increase the risk of foodborne illness.