Mandarin and ginger syrup cake

Ingredients

• Juice of ½ lemon
• 2 tsp finely grated ginger
• 4 eggs
• 75 gm plain flour (½ cup)
• 3 mandarins (about 95gm each), washed, unpeeled
• 270 gm caster sugar (1¼ cups)
• 90 gm melted butter
• 400 gm hazelnut meal
• ⅓ tsp baking powder
• Mandarin and ginger syrup
• 220 gm caster sugar (1 cup)
• 125 ml mandarin juice (½ cup)
• 1 tbsp julienne ginger
• 4 mandarins, peeled and thickly sliced crossways