Preheat your oven to 325°F. Grease a 24-cup mini muffin tin. In a bowl, toss together the finely chopped walnuts, pecans, pistachios, 2 tbsp erythritol, cinnamon, cardamom, and ground cloves.
For the pastry, combine the almond flour, coconut flour, powdered erythritol, and salt in a bowl. Cut in the cold cubed butter using your fingers until the mixture resembles coarse crumbs. Add the egg and mix until a soft dough forms.
Divide the dough into 24 equal pieces. Press each piece into a mini muffin cup, forming a thin shell that comes up the sides. Brush the inside of each shell with melted butter.
Fill each pastry shell generously with the nut mixture, pressing it down lightly. Brush the tops with the remaining melted butter.
Bake for 18 to 22 minutes until the pastry edges are golden and the nut tops are toasted and fragrant.
While the bites bake, make the syrup. Combine the water and allulose in a small saucepan over medium heat. Bring to a simmer and cook for 5 minutes until slightly thickened. Remove from heat and stir in the lemon juice, rose water if using, and vanilla extract.
As soon as the baklava bites come out of the oven, spoon a little syrup over each one, letting it soak into the nut filling and pastry. Let them cool completely in the tin before removing. They get crispier and more flavorful as they sit.
