Step 1

Preheat the oven to 150C fan-forced (170C conventional). Grease and generously line a 30cm x 23cm x 5cm baking tin with baking paper.

Step 2

Cream the butter and sugars until light and pale, for at least 5 minutes – it's important not to rush this step. Beat in the eggs, one at a time, until fully incorporated. Add the vanilla and incorporate, then add the cocoa powder and gently combine. Add the buckwheat flour and stir to combine. Pour the batter into the prepared tin and generously sprinkle with sea salt. Bake for 50 minutes. Remove from the oven and sprinkle again with another pinch of sea salt. Allow to cool completely in the tin before lifting out and slicing.

Step 3

These brownies are best served at room temperature. They can be stored in an airtight container for 3 days at room temperature, and will last for a week in the fridge, just note they become quite solid once refrigerated because of their high butter content.