- Nonstick vegetable oil spray
- 2 cups gluten-free all-purpose baking flour
- 1 1/2 teaspoons baking powder
- 1/2 teaspoon baking soda
- 1/2 teaspoon kosher salt
- 1 1/2 teaspoons ground cinnamon
- 1/2 teaspoon ground ginger
- 1/8 teaspoon freshly grated nutmeg
- 2/3 cup granulated sugar
- 1/4 cup (packed) light brown sugar
- 1/2 cup vegetable oil
- 1/2 cup honey
- 1 large egg
- 1 large egg yolk
- 1/2 vanilla bean, split lengthwise
- 1/2 cup fresh orange juice
- 1/2 cup whey or buttermilk
- 3 ounces cream cheese, room temperature
- 3 tablespoons unsalted butter, room temperature
- 1 cup powdered sugar
- 1 teaspoon finely grated lemon zest
- Pinch of kosher salt
- 1/2 vanilla bean, split lengthwise
- 1 (13.5-ounce) can unsweetened coconut milk, cream separated from milk, room temperature
- Bee pollen, fennel fronds, edible flowers, and berries (for serving; optional)
- Preheat oven to 350°F. Coat a 9″ cake pan with nonstick spray and line bottom with a parchment paper round. Whisk flour, baking powder, baking soda, salt, cinnamon, ginger, and nutmeg in a large bowl to combine.
- Combine granulated sugar, brown sugar, oil, honey, egg, and egg yolk in another large bowl. Scrape in seeds from vanilla bean; discard pod. Using an electric mixer on medium speed, beat mixture until pale and thickened, about 4 minutes. Reduce speed to medium-low and gradually pour in orange juice and whey. Beat until frothy, about 2 minutes. Reduce speed to low and gradually add dry ingredients; beat just until smooth and homogenous (it will be thin, like pancake batter).
- Pour into prepared pan and bake until cake is golden brown and center springs back when gently pressed (a cake tester will not come out clean), 45–55 minutes. Transfer to a wire rack and let cool in pan, 20 minutes. Run a knife around edges of cake to loosen and invert onto rack; let cool completely.
- Cake can be baked 3 days ahead. Store tightly wrapped at room temperature.
- Using an electric mixer on medium-high speed, beat cream cheese and butter in a medium bowl until smooth. Add powdered sugar, lemon zest, and salt and scrape in seeds from vanilla bean; discard pod. Beat on low speed until mixture is very light and thickened, about 2 minutes; scrape down sides of bowl. With motor running, add coconut cream by the tablespoonful and beat until very soft peaks form (save coconut milk for another use).
- Pile frosting on top of cake and spread to edges (it's okay if it cascades over the sides). Decorate with bee pollen, fennel fronds, flowers, and berries, if desired.