Preheat oven to 180°C. Place almonds and sugar in bowl of a food processor and process until finely ground. Combine almond mixture and butter in a medium bowl.

Pack into a 9-inch non-stick springform pan (if pan is not nonstick, brush first with melted butter). Wrap pan with triple layer of heavy-duty aluminium foil, making sure that foil reaches top of side of pan. Bake until lightly golden and set, about 15 minutes and remove from oven. Let cool completely.

Reduce oven temperature to 150°C. Fill a large saucepot with water and bring to a boil over high heat.

Mix cream cheese, mascarpone, sugar, and scrapings from vanilla bean in an electric mixer on low speed until blended. Add vanilla extract. Add eggs, 1 at a time, on low speed. Pour batter into cooled crust.

Place cake pan in a larger roasting pan and fill halfway up side of cake pan with boiling water. Bake for 1 hour and 30 minutes or until edges are set and centre jiggles slightly. Remove from the oven when set.

Remove cake pan from water bath and let cool completely on a wire rack. Place in refrigerator and chill for 4-6 hours or overnight.

Bring sugar and water to a simmer in a medium saucepan over medium-high heat. Reduce heat to medium-low and add blueberries. Cook, stirring frequently, until juices release and thicken and blueberries soften, about 5 minutes. Let cool slightly. Spoon blueberry mixture on top of cooled cheesecake.