Preheat the oven to 350°F. Butter and flour a 10-cup capacity Bundt Pan.
Whisk together the flour, baking powder and salt.
Beat the almond paste with the paddle attachment of a stand mixer until broken into tiny pieces. Add sugar and beat on medium low speed until it becomes sandy. Add butter, a tablespoon at a time, until you've added half. Scrape the bowl frequently. Let the almond, sugar and butter beat on medium-low speed until it becomes a uniform mixture, then add the remaining butter and beat on medium speed until light and fluffy for about 3 minutes.
Add the vanilla and zest.
Add the eggs, one at a time, scraping the bowl between each and allowing the eggs to incorporate before adding the next.
Fold in half the flour, then repeat with remaining flour, just until combined.
Fill the pan with batter, smooth the top and bake for about 45-50 minutes or until a tester comes out clean.
Cool the cake in the pan for 10 minutes, invert onto a cooling rack and allow to cool completely.