Preheat the oven to 350F Line an 8-inch (20cm) square baking pan with foil and spray foil with cooking spray.

Melt the chocolate in the microwave or in a bowl set over a pan of barely simmering water. Whisk in the olive oil and set aside to cool slightly.

Beat the eggs and sugar in a mixing bowl using high speed of an electric mixer for 5 minutes. Beat in the vanilla and salt, then fold in the cooled chocolate mixture. Fold in the flour, then gently stir in the nuts. Pour into the prepared pan.

Bake for 20-25 minutes. Mine became aromatic at 20 minutes and at 25 minutes, they had a shiny, dry, slightly crackly top and looked gorgeous. Let cool completely. Cut into squares.