1. Preheat oven to 425°F (220°C). Whisk eggs, syrup, brown sugar, butter and vanilla in medium bowl until just blended.
2. Place 1 tbsp (15 mL) walnuts in each tart shell. Pour maple syrup mixture over walnuts. Bake in preheated 425°F (220°C) oven until pastry is golden and filling is puffed and just set, about 18 minutes.
3. Serve warm or at room temperature, plain or with lightly sweetened whipped cream.