Flourless orange and ricotta polenta cake

Ingrediënten

• 250g golden (or regular) granulated sugar, plus 2 tbsp for sprinkling
• 2–3 oranges, finely grated for 1½ tbsp zest
• 2 lemons, finely grated for 1 tbsp zest, 20ml juice
• 1 tsp vanilla bean paste or extract
• 250g ricotta
• 4 eggs, 2 whole, 2 yolks
• 100g unsalted butter, well softened
• 175g ground almonds
• 100g polenta (coarse or fine quick-cook, see note)
• 2 tsp baking powder
• ½ tsp fine sea salt
• 35g dried barberries (optional)