Heat the oven to 200C/400F/gas mark 6. Line the bottom and of a 24cm loose-based cake tin with baking parchment. Mix the butter and sugar with an electric mixer until pale, then add the eggs, one at a time. Once all the egg is in, mix together the almonds, buckwheat flour, salt and cinnamon, and fold into the batter. Mix until the batter is smooth, then fold in the walnuts and yogurt.
Pour the batter into the tin and level with a palette knife or a spoon. Cut each fig vertically into halves, and press a little into the batter, cut side up. Bake for 15 minutes, then reduce the temperature to 170C/340F/gas mark 3 and continue baking until it sets - about 40-45 minutes longer, until a skewer comes out clean. Cool down completely before removing from the tin.