Preheat the oven to 350°F (175°C) and lightly grease an 8-inch baking dish.
Toss the blueberries with the sweetener, lemon juice, vanilla, and xanthan gum. Spread the mixture evenly into the baking dish.
In another bowl, combine the almond flour, pecans, cinnamon, salt, sweetener, and melted butter until crumbly.
Sprinkle the crumble evenly over the blueberry mixture without pressing it down.
Bake for 30 to 35 minutes until the topping is lightly golden and the berries are bubbling.
Let the crumble cool for about 10 minutes before serving.
