Preheat the oven to 350°F and line an 8x8-inch brownie pan or baking dish with parchment paper, leaving some overhang for easy removal.
In a medium bowl, whisk together the flour, chocolate protein powder, unflavored protein powder, black cocoa powder, stevia sweetener, and baking powder until well combined.
In a separate large bowl, whisk the applesauce, 1/2 cup nonfat Greek yogurt, 1/3 cup almond milk, egg, egg white, and 2 teaspoons vanilla bean paste until smooth.
Add the wet mixture to the dry ingredients and whisk or stir just until no dry streaks remain; do not overmix.
Pour the batter into the prepared pan and spread it into an even layer with a spatula.
Bake on the center rack for 24 to 26 minutes, or until a tester inserted in the center comes out clean and the cake springs back lightly to the touch.
Let the cake cool in the pan for 10 minutes, then lift it out using the parchment and transfer to a wire rack to cool completely.
Once the cake is completely cool, cut it into strips or small rectangles that will fit back into the 8x8-inch pan in an even layer.
In a large bowl, beat the reduced fat cream cheese with an electric mixer for about 1 minute until very smooth and creamy.
Add 1 cup nonfat Greek yogurt and 2 tablespoons almond milk to the cream cheese and beat until smooth and fully combined.
Beat in the vanilla protein powder, scraping down the sides of the bowl as needed, until the mixture is thick, smooth, and spreadable.
Pour the cooled coffee into a wide, shallow dish.
Working with a few pieces at a time, briefly dip each cake strip into the coffee, turning to coat, then arrange them in a snug single layer in the bottom of the cleaned 8x8-inch pan.
Spread half of the cream mixture evenly over the coffee-soaked cake layer, smoothing the top with a spatula.
Dip the remaining cake strips in the coffee and arrange them in a second even layer over the cream.
Spread the remaining cream mixture over the second cake layer, smoothing the top.
Cover the pan tightly with plastic wrap and refrigerate for at least 6 hours or up to overnight until the tiramisu is fully chilled and set.
Just before serving, sift the unsweetened cocoa powder evenly over the top and sprinkle with the crushed Oreo Thins.
Slice into 12 squares and serve chilled.