Chop the chocolate into small pieces and melt it in a bain-marie. Add the butter until it also melts, then let the mixture cool.
Coarsely chop the walnuts, leaving a few whole. Beat the eggs with the sugar, but without whipping them, and add a pinch of salt. Mix in the melted chocolate, sift in the flour and stir in the chopped walnuts.
Pour into a baking sheet lined with baking paper, then distribute the Amarena Fabbri cherries evenly, pressing them slightly down into the batter.
Finally, place the whole walnuts. Bake at 180°C for about 35 minutes, or until a light crust has formed on the surface. Allow to cool completely in the pan and then cut into squares.