Preheat oven to 350℉. Line a 9 inch round cake pan with parchment paper.
In a large bowl using an electric hand mixer, beat together the eggs and sugar until fluffy - about 1-2 minutes. Next, add in the ricotta cheese, vanilla and beat together until smooth. Add in the olive oil slowly and beat until incorporated. Add in the lemon zest, lemon juice and beat until combined. Sift in the flour, baking powder, salt and mix until ALMOST incorporated. Fold in 1 cup of the blueberries. Transfer batter to the cake pan and spread out evenly. Top with the remaining 1/4 cup blueberries and the sliced almonds. Bake for 40-45 minutes or until toothpick comes out clean. Let it set in the pan for 10 minutes then transfer to your wire rack to cool completely. Sprinkle powdered sugar on top, if you like.
Store leftovers in an airtight container in the fridge for up to 3-4 days.
You can use blackberries or raspberries instead of blueberries.
You can use orange zest and juice instead of lemon.
If you want to make this gluten free, you can use gluten free all purpose flour.
For draining your ricotta, I placed mine on a paper towel lined plate and let it sit for 15 minutes and then dabbed as much moisture as I could from the top.