Special equipment: a 10-cup Bundt pan, nonstick preferred
Preheat the oven to 350 degrees F. Grease a Bundt pan with cooking spray; if your Bundt pan isn't nonstick, oil it and dust with flour.
In a large bowl, combine the flour, cornmeal, baking powder and salt. Whisk until well combined.
In another bowl, stir together the buttermilk, orange zest and orange blossom water.
In a stand mixer fitted with the paddle attachment, cream the butter and sugar together on medium speed until light yellow and fluffy, about 5 minutes. Reduce the speed and mix in the eggs, one at a time. Mix in half the flour mixture, then all of the buttermilk mixture, and, finally, the remaining half of the flour; at each step, mix until just combined. Pour the batter into the prepared Bundt pan.
Bake on the middle rack until golden brown and just beginning to pull away from the edges, 35 to 40 minutes. Cool the cake in the pan on a rack for 20 minutes.
Meanwhile, make the ganache: Bring the cream to a simmer in a heavy-bottomed saucepan over medium heat, about 3 minutes.
While the cream is heating, combine the white chocolate chips, orange zest and orange extract in a heat-proof glass bowl, and set the bowl over the cream. When the cream reaches a simmer, pour it over the chocolate and let sit for 1 minute to begin to melt; then stir with a rubber spatula until smooth. Allow to cool slightly, about 10 minutes, stirring every couple minutes to ensure even cooling.
Invert the cake onto a rimmed plate and drizzle the top with ganache. Serve warm or at room temperature.