Preheat your oven to 325°F (160°C).
Toast the whole wheat bread slices until very crisp and dry, then pulse them in a food processor until they become fine crumbs.
Press the bread crumbs firmly into the bottom of a small, lightly greased 4-inch springform pan or oven-safe ramekin to create the crust.
In a medium mixing bowl, whisk together the Greek yogurt, egg whites, vanilla protein powder, monk fruit sweetener, and lemon juice until the batter is completely smooth and lump-free.
Pour the yogurt mixture over the prepared bread crumb crust.
Bake for 25-30 minutes, or until the edges are set but the center still has a slight jiggle when moved.
While the cheesecake is baking, combine the mixed berries and honey in a small saucepan over medium heat.
Simmer the berries for 5-8 minutes, stirring occasionally, until they break down and the liquid reduces into a thick, jammy sauce.
Remove the cheesecake from the oven and let it cool to room temperature, then place it in the refrigerator to chill for at least 2 hours.
Top the chilled cheesecake with the warm or cooled berry compote before serving.