Pre-heat oven to 350F and grease a 9-inch springform pan.
In a large bowl, whisk together the flours, sugar, baking soda, cinnamon and salt.
Add in the milk, oil, egg and lemon juice and zest, and stir until all the dry ingredients are well incorporated. Pour into a greased springform pan and arrange the raspberries on top, poking them into the batter a little bit.
Prepare the crumb topping by stirring together the buckwheat flour, cane sugar and sliced almonds in a small bowl. Add in the melted coconut oil and stir until a crumbly mixture forms. Sprinkle on top of the raspberries.
Bake for 34 – 37 minutes, or until the edges of the cake are browned and crispy, and a toothpick inserted into the middle of the cake comes out clean. Let cool on a wire rack before slicing and serving.
Buckwheat flour comes in both light and dark varieties. I used light in this recipe. If you use dark, your cake and topping will look very dark.
If you don’t have cane sugar, you can substitute coconut sugar or brown sugar in both the cake and crumb topping. You can also use granulated sugar in the cake, but stick with a courser sugar for the topping.
You can use frozen berries, just be sure to thaw them first before adding them to the cake.
I made this cake in a 9-inch springform pan, but you can also use a high rimmed pie plate or cast iron skillet.
If the crumb topping starts to brown too much on top, just cover the cake with foil for the last few minutes of baking.
You can add a light dusting of icing sugar to the top of the cake before serving. But keep in mind that icing sugar contains cornstarch, and therefore, the cake will not be grain-free.