Preheat your oven to 180°C (350°F). Grease the cake pan and line the bottom with parchment paper to prevent sticking.
In a large bowl, whisk together the olive oil and sugar until the mixture looks slightly frothy and well combined, about 2 minutes. You should smell a fragrant aroma of fruity olive oil.
Add the eggs one at a time, whisking well after each addition. The batter will become smooth and slightly thickened, with a glossy appearance.
Zest the lemon directly into the batter, then gently fold in to brighten the flavor and enhance the olive oil aroma.
Sift the flour and baking powder together over the wet ingredients to aerate them. Gently fold the dry ingredients into the batter until just combined, being careful not to overmix. The batter should be smooth but light.
Pour the batter into the prepared cake pan, smoothing the top with a spatula. Gently tap the pan on the counter to release any trapped air bubbles.
Bake in the center of the oven for 35 to 40 minutes. The cake is ready when the top is golden, fragrant, and a toothpick inserted into the center comes out clean.
Remove the cake from the oven and let it cool in the pan for 15 minutes. Then, transfer it to a wire rack and cool completely to set the crumb.
Once cooled, slice and serve. The cake should be moist, tender, and aromatic with bright citrus and fruity olive oil notes. Enjoy as is or dust lightly with powdered sugar for a simple finish.