1. For the streusel topping add spelt flour, brown sugar, cinnamon, and salt to a bowl and mix to combine. Add the butter in small pieces and mix in. Rub everything between your fingers until you get different-sized streusels. Add the chopped walnuts and mix in. Set aside until needed.

2. Preheat the oven to 350°F (180°C). Grease a 9×13 inches (23x33cm) baking pan lightly and set aside.

3. Add the pumpkin purée, oil, yogurt, brown sugar, eggs, milk, and maple syrup to a large bowl and mix until well combined. Mix the spelt flour, rolled oats, baking powder, baking soda, pumpkin pie spice, and salt. Add to the large bowl and mix until just combined – do not overmix. Pour the batter into the prepared baking pan, sprinkle the streusels on top, and bake for 60-65 minutes or until a wooden skewer inserted into the center of the cake comes out clean. Take the cake out of the oven and let cool down completely inside the baking pan.

4. For the glaze mix confectioners’ sugar with heavy cream, maple syrup, and vanilla extract until you get a thick and smooth glaze. Drizzle over the cake and serve.