- With the rack in the middle position, preheat the oven to 180 °C (350 °F). Butter a 20-cm (8-inch) springform pan and line the bottom with parchment paper.
- In a food processor, grind the chopped nuts and half the sugar. Set aside in a bowl and add the flour, baking powder, and salt. Stir to combine. Set aside.
- In another bowl, beat the eggs with the remaining sugar until the mixture is light and triples in volume. Add the oil in a stream. With a spatula, gently fold in the dry ingredients alternately with the Armagnac until smooth. Spread in the pan.
- Place the walnuts pieces over the cake to create a checkerboard pattern. Bake for 45 to 50 minutes or until a toothpick inserted in the centre of the cake comes out clean. Let cool for about 30 minutes. Remove from the pan and drizzle with the honey. Cool completely. If desired, serve with cream whipped with a little honey.