Preheat your oven to 350 degrees Fahrenheit. Grease and flour a 9-inch round cake pan thoroughly, especially around the sides.

In a large bowl, cream together the softened butter and granulated sugar until light and fluffy. Beat for about 3 minutes for the best air incorporation.

Add the eggs one at a time, beating well after each addition. Scrape down the sides of the bowl as needed.

In a separate bowl, whisk together the all-purpose flour, baking powder, and salt.

Gradually add the dry ingredients to the creamed mixture, alternating with the pineapple juice. Begin and end with the flour mixture. Stir in the vanilla extract until just combined. Do not overmix.

Pour the cake batter into the prepared pan and smooth the top gently with a spatula.

To make the filling, combine the drained crushed pineapple, sugar, and cornstarch in a small saucepan. Cook over medium heat for about 5 to 7 minutes, stirring frequently, until the mixture thickens. Remove from heat and let it cool slightly for 5 minutes.

Spoon the pineapple filling over the cake batter. Gently swirl it with a knife using a figure-eight motion. Avoid stirring too much.

Bake for 50 to 60 minutes, or until a toothpick inserted into the center comes out clean. Because the filling is moist, test a few spots if needed.

Allow the cake to cool in the pan for 10 minutes. Run a thin knife around the edge, then turn it out onto a wire rack to cool completely.

To prepare the glaze, mix the powdered sugar with 3 tablespoons pineapple juice in a small bowl. Add more juice a teaspoon at a time until the glaze is thick but pourable.

Drizzle the glaze over the cooled cake. If using lemon zest, sprinkle it over the top before the glaze sets.

Serve the cake at room temperature or slightly chilled.