Preheat your oven to 350°F (175°C). Lightly grease a 9-inch round cake pan with butter or nonstick spray. Optionally, line the bottom with parchment paper for easy release.

In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside—this mixture ensures an even rise and texture.

In a large bowl, cream the softened butter and granulated sugar until the mixture is pale and fluffy. This should take about 2–3 minutes using a hand or stand mixer.

Beat in the eggs one at a time, mixing well after each addition. Add the vanilla extract and beat until combined.

With the mixer on low, add the dry ingredient mixture in thirds, alternating with the pineapple juice and milk. Begin and end with the dry ingredients. Mix only until just combined—do not overmix.

Using a spatula, gently fold in the drained crushed pineapple until evenly distributed. The batter will be thick but pourable.

Pour the batter into the prepared cake pan and smooth the top. Bake for 30–35 minutes, or until the top is golden and a toothpick inserted into the center comes out clean.

Let the cake cool in the pan for 10 minutes. Then transfer it to a wire rack to cool completely before slicing.