Preheat your oven to 350°F (180°C). Prepare a 9-inch loose-bottom cake pan by lining it with parchment paper or greasing it.

In a mixing bowl, combine 2 cups ricotta, 7 tablespoons sugar, 1 egg, zest from 1½ lemons, 1 tablespoon lemon juice, and 1 teaspoon vanilla extract. Mix until smooth.

In a large bowl, whisk together 2¼ cups flour, 2 teaspoons baking powder, and zest from the remaining ½ lemon. Add in the beaten egg and 6 tablespoons olive oil. Mix until crumb-like.

Take two-thirds of the crumb mixture and distribute it across the bottom and up the sides of the prepared pan, pressing down lightly.

Pour the ricotta mixture into the crumb shell and spread it evenly.

Sprinkle the remaining crumb mixture over the ricotta filling evenly.

Bake the cake for about 30 minutes or until the top is lightly golden and a toothpick inserted comes out clean.

Cool the cake in the pan for about 10 minutes, then release the bottom of the pan and allow it to cool completely on a wire rack. Dust with icing sugar before serving.