Preheat oven to 350˚F/ 180˚C. Line the bottom of a 9-inch springform pan with parchment paper, then lightly grease the paper and sides with olive oil.
In a large bowl, mix ricotta and brown sugar together until smooth, about 5 minutes. Add the eggs in one at a time, mixing well after each addition.
Add the lemon zest, olive oil, lemon juice and vanilla extract and mix until combined.
In a separate medium bowl, sift together the all-purpose flour, almond flour, baking powder and salt.
Add about half of the flour mixture to the wet ingredients and fold until incorporated. Add the remaining flour mixture and fold until just combined. Scrape the batter into the prepared pan and smooth the top into an even layer.
Sprinkle the top of the batter with the ground almonds and bake for 40 to 50 minutes or until a cake tester inserted in the center comes out clean.
Let the cake cool for 30 minutes, then remove the springform ring and transfer to a serving platter until completely cool. Dust with powdered sugar right before serving.
Serves 6-8