Preheat your oven to 350°F (175°C). Line an 8×8-inch baking pan with parchment paper, leaving a slight overhang on the sides. This makes it easy to lift the bars out later. In a large mixing bowl, whisk together the oat flour, vanilla protein powder, baking powder, ground ginger, and salt until no clumps remain.

In a separate medium bowl, combine the Greek yogurt, egg whites, maple syrup, vanilla extract, and orange zest. Stir until the mixture is smooth. Pour the wet ingredients into the dry ingredients and fold gently with a spatula. Once nearly combined, fold in the dried cranberries and white chocolate chips. Do not overmix, as this can make the protein powder texture too tough.

Spread the batter evenly into the prepared baking pan. Use the back of a spoon or a wet spatula to smooth the top. Bake for 16 to 18 minutes. The edges should be lightly golden, and a toothpick inserted into the center should come out clean. Remove the pan from the oven and let the base cool completely before frosting.

While the bars cool, prepare the frosting. Beat the softened light cream cheese, 1/2 scoop of protein powder, and orange juice together until creamy. Spread the frosting over the cooled bars. Sprinkle with extra chopped cranberries and drizzle with a little melted white chocolate if desired. Slice into 12 even bars and serve.