Preheat oven to 300 degrees.
Grease and flour a (10-cup) bundt pan or two small loaf pans.
In a large mixing bowl using an electric mixer, beat the butter and granulated sugar until light and fluffy. Add the vanilla bean paste and salt. Mix just until blended. Slowly add the buttermilk and mix just until blended.
Alternate adding the eggs, one at a time, with the flour, beating just until the yolk disappears and the flour is incorporated. Do not over-beat.
Scrape down the sides of the bowl as needed. Add the drained pineapple and fold in gently using a rubber spatula just until blended.
Pour the batter into the prepared pan and smooth the top to distribute evenly. Bake at 300 degrees for 1 hour, 15 minutes to 90 minutes. Check the cake using a toothpick. There should be no wet batter on the toothpick. Moist crumbs is normal.
Allow the cake to cool before inverting onto a serving plate. Store leftovers in cake-taker or freeze in an airtight container.
To make the glaze combine the reserved pineapple juice and about 1 cup powdered sugar to make a glaze. Whisk until smooth. Add more or less sugar for proper consistency. Drizzle over cooled cake.