Step 1Heat the oven to 325 degrees.
Step 2Place the butter and sugar in the bowl of an electric mixer and beat to a creamy consistency. Once the mixture is smooth, add the flour, cornmeal and ginger, and mix to combine. Press the dough evenly into the bottom of a 9-inch springform pan.
Step 3Bake until golden brown, about 8 to 10 minutes.
Step 1Place the cream cheese, sugar and vanilla bean seeds in the bowl of an electric mixer and cream until smooth. Beat in the eggs and egg white, scraping down the sides of the bowl. Add the vanilla extract, lemon juice, creme fraiche and cream and mix well.
Step 2Pour into the baked crust and bake until the center is set, 50 to 55 minutes.
Step 3Refrigerate the cheesecake 2 to 4 hours before removing it from the pan.
Step 1Set aside half of the blackberries and half of the raspberries.
Step 2Combine the remaining blackberries and raspberries, the sugar and the ginger in a saucepan. Cook on low to medium heat until the berries have released all their juices, about 15 minutes.
Step 3Strain through a fine strainer, pressing down with a wooden spoon, and return the liquid to the saucepan, discarding the solids. Cook until the sauce is reduced by two-thirds. Drizzle the sauce over the chilled cheesecake and garnish with the reserved berries.