Preheat the oven to 350°F (180°C) and grease a 7-inch springform pan with oil or line it with parchment paper.
Strain the ricotta cheese by removing any extra liquid that has formed on top.
In a large bowl, whisk together ricotta cheese, egg, honey, and lemon juice until smooth.
Sift in almond flour, cornstarch and baking powder, then fold gently until fully combined; there should be no lumps left in the batter.
Pour the batter into the pan and bake for 25-30 minutes, or until the top is golden and a toothpick inserted into the center comes out clean.
Let cool for at least 15 minutes before serving, garnished with a sprinkle of powder sugar or fresh berries on top.