1Preheat oven to 350°F.
2Prepare crust: In a food processor, purée flour, oats and almonds until they become a fine powder. Add sugar, butter, vanilla, cinnamon and salt. Pulse until combined and crumbly
3Spray an 8"springform pan with non-stick cooking spray. Gently press crust evenly into bottom of springform pan. Place pan in oven and bake for 30 minutes or until crust is golden brown. Remove from oven and let cool at room temperature. Increase oven temperature to 500°F.
4Prepare filling: Place cream cheese, sugar, lemon juice and vanilla into the bowl of the food processor. Pulse until smooth and combined. Add yogurt, egg, egg whites and salt; pulse again until smooth. Pour filling into cooled crust.
5Place cheesecake in the center of a 14" square piece of aluminum foil. Wrap pan entirely with aluminum foil to prevent water from seeping into the bottom of the pan. Place into a bain marie and bake for 10 minutes. Reduce oven temperature to 200F and continue to bake for 60 minutes until just slightly wobbly in the center and a thermometer inserted into the center of the cake reads 150F.
6Transfer cake to a wire rack and allow to cool for 5 minutes. Run a thin, sharp knife between cake and sides of pan. Allow to cool at room temperature for about 2 hours. Wrap with plastic wrap and refrigerate for a minimum of 3 hours, and up to 3 days.
7While cake is cooling, prepare topping: Combine berries, lemon juice, sugar, and ¾ cup water in a medium saucepan. Bring to a boil over high heat, reduce heat to medium-low and simmer for about 15 minutes. Transfer to a blender or food processor and purée until smooth. Return sauce to pot, and return to medium-low heat. In a small bowl stir arrowroot powder with 1 tbsp until smooth to form a slurry. Stir into berry mixture and cook, stirring frequently for about 2 minutes. Remove from heat, allow to cool to room temperature, cover and refrigerate.
8To serve, fill a pitcher or bowl with warm water. Using a sharp knife, slice cheesecake into 12 servings, dipping knife into water and carefully wiping it clean with a towel after each slice. Dollop each serving with berry topping and garnish with fresh berries (optional). Serve immediately
9Cheesecake will keep, covered and refrigerated, for up to 3 days