Preheat your oven to 350°F (175°C) and prepare your baking pan.
In a large mixing bowl, sift together the flour, cocoa powder, baking powder, and salt.
In a separate bowl, whisk together the eggs, sugar, and vegetable oil until well combined.
Add the ricotta cheese and vanilla extract to the egg mixture, and whisk until smooth.
Gradually add the dry ingredients to the wet ingredients, mixing gently until just combined.
Pour the batter into the prepared pan and smooth the top with a spatula.
Bake in the preheated oven for 25-30 minutes, or until a toothpick comes out clean.
Allow the cake to cool in the pan for 10 minutes before transferring to a wire rack.
Once cooled, dust with powdered sugar before serving.