Italian ricotta doughnuts with citrus curd

Ricotta

• 1800 g full cream milk
• 80 g white vinegar

Citrus curd

• 30 g orange juice (approx. ½ orange)
• 20 g lemon juice (approx. ½ lemon)
• 110 g caster sugar
• 80 g unsalted butter softened
• 2 eggs

Ricotta doughnuts

• 1 egg
• 120 g caster sugar
• 150 g plain flour
• 50 g full cream milk
• 2 tsp baking powder
• ¼ lemon zest only, grated, no white pith
• 1500 g vegetable oil for deep frying
• 1 tsp ground cinnamon