Preheat your oven to 175°C (350°F) and grease a 9-inch round cake pan with olive oil.

In a medium bowl, whisk together the ground almonds, all-purpose flour, baking powder, cinnamon, and salt until well combined.

In a large mixing bowl, combine the granulated sugar, eggs, and olive oil. Whisk until smooth, then stir in the orange juice, orange zest, and vanilla extract.

Gently fold the dry ingredients into the wet ingredients using a spatula until just combined.

Pour the batter into the prepared cake pan and bake for 30-35 minutes or until golden brown and a toothpick comes out clean.

Prepare the syrup by simmering sugar, water, cinnamon stick, and lemon juice in a saucepan until the sugar dissolves. Simmer for 5 minutes.

Let the cake cool for 10 minutes, then pour the warm syrup evenly over it.

After the cake cools completely, gently transfer it to a serving plate, slice, and serve.