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1
Preheat oven to 350 F with a rack in the lower third. Spray a 12-cup bundt pan with nonstick cooking spray with flour (or grease with butter and lightly coat with flour).
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2
In a large bowl, combine 1 1/2 cups of the sugar and the zest. Rub the zest into the sugar with your fingertips until the sugar is moist and fragrant. Add the flour, salt, baking powder, and baking soda to the bowl containing the sugar/zest mixture and whisk to combine everything. In a large measuring cup, whisk the milk, egg yolks, oil, butter and vanilla.
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3
In the bowl of a stand mixer fitted with the whisk attachment, beat the egg whites on low speed until foamy. Add the cream of tartar then increase the speed to medium-high. With the mixer running, add the remaining 1/2 cup of sugar, a little at a time, and continue beating until the whites are shiny and form stiff peaks.
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4
Add the milk mixture and lemon juice to the dry ingredients and whisk until smooth. Add one third of the egg whites to the bowl and stir to combine (to lighten the batter) then add the remaining egg whites and gently fold to incorporate (try not to deflate the whites).
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5
Pour the batter into the prepared pan. Bake for about 40-45 minutes, or until a toothpick inserted in the center of the cake comes out with a few moist crumbs attached. Transfer the pan to a wire rack and cool for 10 minutes then turn the cake out onto the rack to cool completely.
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6
To make the glaze: Whisk everything together in a medium bowl until smooth. Drizzle over the cake letting it run down the sides. Let the glaze set for about 15 minutes.
