Preheat oven to 425°F (220°C). Dust countertop with flour and roll pastry into a 12 x 12-in. (30 x 30 cm) square. Transfer to a parchment paper-lined baking sheet. Fold in edges of pastry to make a 1/2-in. (1 cm) border.
Mix chopped almonds, 1/4 cup (60 mL) sugar and 1 tbsp (15 mL) flour in a small bowl. Scatter over bottom of pastry. Spread 2 cups (500 mL) blueberries in a single layer over mixture and sprinkle with remaining 1 tbsp (15 mL) of sugar.
Bake 20 min. or until edges are lightly browned and bottom of tart is cooked. Sprinkle with remaining fresh blueberries. Serve warm or at room temperature.