1. Heat oven to 400 degrees . Lightly coat a baking sheet with nonstick cooking spray.
2. Unfold pastry sheet on prepared baking sheet. Cut a 1-inch-wide strip from each long side. Brush a 1-inch-wide strip along the 2 long sides with water. Lay a cut strip along each side to form a border. Brush bottom of tart with 2 tbsp of the agave nectar and sprinkle thyme over the bottom. Using a fork, prick bottom of pastry all
3. Bake at 400 degrees for 16 to 17 minutes or until nicely browned. Transfer baking sheet to a wire rack; let cool. Gently press down center of tart if puffed.
4. Fan plums and blackberries in a decorative pattern over tart. Drizzle remaining 2 tbsp agave nectar over top. Whip goat cheese and milk and dollop over top. Return to oven for a few minutes to gently heat fruit and goat cheese. Serve warm or at room temperature.