Preheat the oven to 175°C. Grease a bundt pan with butter and dust it with rice flour or potato fiber.
Mix dry ingredients: In a large bowl, combine the rice flour, potato fiber, cornstarch, baking powder, cinnamon, cardamom, ginger, and salt.
Whisk eggs and sugars: In a separate bowl, whisk together the eggs, brown sugar, and granulated sugar until light and fluffy. Add the oil and vanilla, whisking until well combined.
Add psyllium gel, grated apple, and almond paste: Fold the psyllium gel, grated apple, and grated almond paste into the egg mixture. Add oil. Gently fold the mixture.
Combine: Gently fold the dry ingredients into the wet mixture until just combined. Avoid over-mixing.
Bake: Pour the batter into the prepared bundt pan. Place the pan on a lower oven rack and bake for about 50–55 minutes, or until a toothpick inserted in the center comes out clean.
Cool: Allow the cake to cool in the pan for about 15 minutes before carefully inverting it onto a wire rack to cool completely.
Make the glaze: In a saucepan, melt the butter over medium heat. Add the 75 g of brown sugar, brewed coffee, and cinnamon, stirring until the sugar is dissolved. Remove from heat and whisk in the milk until you reach a smooth, pourable consistency.
Drizzle the glaze: Once the cake is cooled, drizzle or brush on the glaze over the bundt cake before serving.
Serving suggestion:Dust with powdered sugar, or serve with a dollop of whipped cream or vanilla ice cream for an extra treat!