Preheat the oven to 165°C (325°F). Butter and flour a 20 cm (8 inch) springform pan.
In a bowl, use a rubber spatula to combine the Ricotta, icing sugar, flour, cornstarch, egg yolks, lemon zest, lemon juice, and turmeric. Set aside.
In another bowl, beat the egg whites with an electric beater until stiff peaks form. Using the spatula, gently fold the meringue into the Ricotta mixture.
Pour the batter into the springform pan and bake in the oven for approximately 60 minutes.
Let the cake cool, cover with plastic wrap, and refrigerate for 4 hours or overnight.
Before serving, unmould the cake and dust with icing sugar.
