Pre-heat oven to 325°. Line a rimmed 9"x13" baking sheet with parchment paper, set aside.
In a small saucepan, bring blueberries, lemon juice, and 2 tbsp sugar to a boil over medium-high heat, then lower heat to continue simmering blueberries for 5 more minutes until blueberries have burst. Whisk cornstarch into water, then whisk into blueberries and return to a boil. Remove from heat and set aside in refrigerator.
Mix dry crust ingredients, then stir in wet ingredients except egg. Once combined, add egg and whisk until smooth. Pour into lined baking sheet and spread evenly. Set aside.
To a large bowl or stand mixer, add the Greek yogurts and cream cheese for the cheesecake layer. Add sugar and protein powders on top, then starting on low speed using a hand mixer or stand mixer, mix until powders are mostly incorporated. Increase speed to medium-high and blend until smooth. Add lemon extract, lemon zest, and egg whites, then continue mixing until smooth, ensuring you don't lose any lemon zest to the mixer attachments (it sticks).
Pour cheesecake mixture over crust and spread evenly. Add blueberry mixture on top of cheesecake by the spoonful, then swirl with a knife.
Bake at 325° for 25 minutes, or until edges are just golden brown and center of cheesecake barely jiggles when bumped. Allow to cool to room temperature, then refrigerate at least 4 hours before cutting.
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