Preheat the oven to 400F (200°C)
Roll out the puff pastry on a lightly floured surface and trim it into a rectangle, approximately 10x6 inches. Use a fork to prick holes across the surface—this helps the tart base bake up crispier.
Spread the whipped goat cheese mixture evenly over the puff pastry base.
Arrange the roasted beet slices on top, slightly overlapping them in a shingled pattern for visual appeal. Leave about an inch of space around the edges, then fold the edges inward to create a border for the tart.
Brush the puff pastry border with egg wash to give it a golden, glossy finish when baked.
Bake for 12–15 minutes, or until the pastry is puffed and golden brown. Let the tart cool slightly, then garnish and serve.