Preheat the oven to 350°F and line an 8x8-inch baking pan with parchment paper, leaving some overhang on two sides for easy lifting.
In a large bowl, whisk the melted butter and golden monk fruit sweetener until glossy, then whisk in the egg and vanilla extract. Fold in the almond flour, baking powder and salt until a thick, soft dough forms.Spread the dough evenly into the prepared pan, pressing it into the corners with a spatula.
In a separate bowl, beat the softened cream cheese and powdered sweetener until completely smooth. Add the egg yolks, heavy cream and vanilla bean paste and mix on low speed just until combined and silky.
Pour the custard over the blondie base and smooth it into an even layer. Bake for 28 to 32 minutes, until the edges are golden and the center still has a slight jiggle.
Let the blondies cool completely in the pan, then refrigerate for at least 3 hours so the custard layer sets firm and creamy.
Lift the chilled blondies out of the pan and sprinkle the granulated allulose in a thin, even layer over the top. Use a kitchen torch to caramelize the surface until it turns deep amber and crackly.Let the sugar shell harden for 2 minutes, then cut into squares and serve right away for the best crack.