1. Preheat the oven to 325F (160C). Butter two shallow 10-inch (23cm) cake pans and line each with a circle of parchment paper. Then lightly butter the top of each circle of paper.
2. Beat the butter, sugar and salt until smooth.
3. Meanwhile, pulverize the nuts and flour in a food processor or blender until relatively fine, but not powdery. If you don’t have a machine, simply chop the nuts by hand and toss them with the flour.
3. Beat in the eggs one at a time. Afterwards, stir in the ground nut mixture and the carrots, mixing just until smooth.
4. Divide the batter into the pans, smooth it evenly, and bake for 40 minutes, until a toothpick inserted into the center comes out clean.
Cool, then release the cake from the pans and cut in wedges to serve.