Before you start, preheat oven to 220°C (or 200°C fan bake).
Prep beetroot and toss on a lined oven tray with oil and balsamic vinegar. Season with salt and pepper and roast for 15-20 minutes, until almost tender.
Meanwhile, unroll pastry and lay on a lined oven tray. Use a small, sharp knife to score a 1cm border around the edge of the pastry. Using a fork, prick the base of the pastry, inside the border. Place hand flat on top of figs and slice through horizontally. Prep feta. Set both aside.
Using a half tablespoon measure, roll pork and fennel grind into small meatballs. Heat oil in a medium fry-pan on medium heat. Cook meatballs for 4-5 minutes. Remove from heat and set aside.
Top tart with dollops of caramelised onion jam/relish. Top with cooked beetroot, figs and meatballs. Sprinkle over feta and almonds.
Bake tart for 15-20 minutes, until beetroot is tender and pastry is golden.
Just before serving, toss mesclun in a small bowl with vinegar.
To finish, transfer cooked tart to a chopping board and cut into wedges.
Serve tart topped with mesclun.