Preheat your oven to 350°F (175°C). Line an 8x8 inch baking pan with parchment paper.
Make the cream cheese swirl. In a medium bowl, beat the softened cream cheese with the monk fruit sweetener until smooth. Add the egg yolk and vanilla extract and beat until creamy and completely combined. Set aside.
In a large bowl, whisk together the melted butter and golden monk fruit sweetener. Add the eggs and vanilla extract and whisk until thick and smooth.
Add the almond flour, baking powder, and salt. Stir with a spatula until a thick batter forms with no dry spots remaining.
Spread the blondie batter evenly into the prepared pan. Drop large spoonfuls of the cream cheese mixture across the surface. Use a toothpick to drag through both batters, creating an elegant marbled swirl pattern.
Bake for 25 to 28 minutes, until the blondie portion is golden and the cream cheese swirl is set but not browned. A toothpick should come out mostly clean.
Let cool completely in the pan. For the cleanest slices, refrigerate for at least 1 hour before cutting into 16 squares. Serve chilled or at room temperature.