1. Preheat the oven to 400°F.
2. Combine all of the ingredients for the almond cream in a blender or food processor. Blend until a smooth mixture forms, scraping down the sides as needed. Set aside.
3. On a lightly floured surface, roll out the puff pastry to a rough rectangle about ¼” thick. Place the pastry on a parchment-lined baking sheet. Set aside.
4. Place the blueberries in a medium-sized bowl. Add in the rest of the blueberry filling ingredients and stir well to evenly coat the berries.
5. Spread the almond cream over the pastry, leaving a 1-2″ (2.5-5 cm) border of pastry uncovered.
6. Carefully spoon the blueberries over the almond cream. Fold the edges of the pastry up and over the blueberry filling.
7. Bake in the preheated oven for 40-45 minutes, or until the center is bubbling gently and the crust is golden brown. Let cool for about 10 minutes before slicing. The filling will set as it cools further, allowing for tidier slices.
8. Serve on its own, or with a dollop of whipped dairy-free cream or a scoop of ice cream.
9. Store in an airtight container (or wrap in cling wrap) in the refrigerator for up to 5 days. The pastry will soften. To re-crisp the pastry, preheat the oven to 350°F. Heat the tart in the oven for about 15 minutes.