Preheat your oven to 175°C (350°F) and grease a rectangular baking pan (23 x 33 cm) with butter or line it with parchment paper.

In a large mixing bowl, combine the all-purpose flour, granulated sugar, cocoa powder, baking powder, and salt. Whisk until well blended.

In another bowl, whisk together the eggs, vegetable oil, and vanilla extract until smooth.

Pour the wet mixture into the dry ingredients and gently stir until combined.

Pour the batter into the prepared baking pan and smooth out the top with a spatula.

Bake in the preheated oven for 40 to 45 minutes, checking for doneness with a toothpick.

Once baked, let the cake cool in the pan for about 10 minutes before transferring to a wire rack to cool completely.

Dust the cooled cake with powdered sugar for a lovely visual touch.

Slice into squares and serve warm or at room temperature.