• Preheat oven to 325 degrees. Line the bottom of a 10-inch tube pan with parchment paper (do not grease the sides); set aside.
• In a large mixing bowl, whisk together the flour, sugar, coconut, baking powder, and salt.
• In a medium mixing bowl, whisk together the egg yolks, lime juice, coconut oil, water, lime zest, and vanilla extract. Make a small well in the center of the dry ingredients and pour the wet ingredients in. Mix just until combined, taking care not to over-mix.
• In the bowl of a stand mixer fitted with the whisk attachment (or with a hand mixer fitted with the whisk attachment), combine egg whites and cream of tartar. Beat on medium for 1 minute, then gradually increase the mixing speed to medium-high and beat for 3 to 4 minutes or until stiff peaks form. Use a large rubber spatula to gently fold the egg whites into batter.
• Pour the batter into the prepared pan, then gently tap the pan on the counter 3 times to remove air bubbles. Place in the oven and bake for 45 to 55 minutes, or until top is golden and a toothpick inserted in the center comes out clean.
• Invert pan and let cake cool for about 90 minutes. Once the cake has cooled, run a thin knife around the edge to loosen and invert onto a serving platter (I have a thin wire cake tester that I use for this).

To make the Glaze

• Whisk all of the ingredients together in a small mixing bowl. Poke the top of the cake several times with a toothpick or cake tester, then drizzle the glaze over cooled cake. Allow the glaze to set, about 10-15 minutes. Garnish before serving, if desired.