Preheat the oven to 375°F (190°C). Peel, core, and cut the apples into small cubes. Toss them with melted butter, cinnamon, and a little brown sugar. Spread on a lined baking sheet and roast for 15–20 minutes until caramelized and tender. Let cool slightly.

Lower the oven to 350°F (175°C). Grease the pan thoroughly with butter, coating every nook and cranny, then dust with flour or almond flour.

While apples roast, toast the walnuts in a dry skillet over medium low heat until fragrant and lightly golden. Set aside to cool.

In a small saucepan, melt the butter over medium heat, swirling occasionally, until it turns golden brown and smells nutty. Remove from heat and let cool slightly.

In a medium bowl, whisk together all-purpose flour, oat flour, almond flour, baking powder, baking soda, a pinch of salt, cinnamon, and cardamom.

In a large bowl, whisk the browned butter with coconut sugar until combined. Add eggs one at a time, then stir in Greek yogurt, vanilla, grated ginger, and orange zest.

Gently fold the flour mixture into the wet ingredients until just combined. Then fold in the roasted apple filling and toasted nuts.

Spread the batter evenly in the prepared bundt pan and place it in the preheated oven. Bake 55–65 minutes, or until a toothpick inserted into the center comes out clean.

Let the cake cool in the pan for 15 minutes, then carefully invert onto a wire rack to cool completely. Whisk together powdered sugar, orange juice, and orange zest for the glaze, then drizzle over the cooled cake.