Preheat your oven to 350°F (175°C). Grease and flour an 8-inch round cake pan or line it with parchment paper.
In a large mixing bowl, beat the egg yolks and granulated sugar together until the mixture is pale and creamy.
Sift together the flour, baking powder, and salt. Gradually add this dry mixture to the egg yolk mixture, alternating with the milk and vanilla extract. Mix until just combined.
In another clean bowl, beat the egg whites and cream of tartar until stiff peaks form.
Gently fold the beaten egg whites into the batter in three additions, being careful not to deflate the mixture.
Pour the batter into the prepared cake pan and smooth the top.
Bake for 25-30 minutes or until the cake is golden and a toothpick inserted in the center comes out clean.
Allow the cake to cool in the pan for 10 minutes, then turn it out onto a wire rack to cool completely.
Once cooled, dust the top with powdered sugar if desired before serving.