Preheat the oven to 180 and line a baking tray with baking paper.
Cut the pastry into circles using a round cookie cutter or large wine glass and space out on the lined baking tray.
Using a smaller glass or cookie cutter, gently press in the center of each pastry round to create a frame for the filling but be careful not to push all the way through the pastry. Using a fork poke the center of each pastry round.
Fill each center circle with onion marmalade and top with sliced beetroot and little balsamic reduction.
Egg wash the edges of the pastry, so it goldens up nicely in the oven.
Place the tray in oven and bake for 10 minutes or until the pastry puffs up around the filling and turns golden.
Remove from the oven and generously crumb the Puhoi Valley Feta Cheese over each tartlet.