Preheat your oven to 350°F (175°C). Grease and flour a cake pan.
In a mixing bowl, cream together the butter and sugar until light and fluffy.
Add the eggs one at a time, beating well after each addition. Stir in the vanilla extract.
In another bowl, combine the flour, baking powder, and salt. Gradually add to the creamed mixture alternately with the milk, beginning and ending with the flour mixture.
Pour the batter into the prepared cake pan. Bake for 35-40 minutes, or until a toothpick inserted into the center comes out clean.
While the cake is baking, prepare the quince glaze. In a small saucepan, combine the quince jelly and water. Cook over low heat until the jelly is melted and smooth.
Once the cake is done, let it cool in the pan for 10 minutes, then transfer to a wire rack. Brush the warm quince glaze over the top of the cake. Let it cool completely before serving.