Preheat the oven to 350 F. Line an 8inch square pan with baking paper.
Combine the melted butter, egg, both sugars, coffee and vanilla in a medium bowl and stir well.
Add in the flour, baking soda and salt until just incorporated.
Set aside about half a cup of dough and press the remaining mixture into the base of the prepared baking pan.
Drop spoonfuls of the Nutella over the cookie dough base, make the layer even. Pour the condensed milk over the Nutella layer. Sprinkle the chopped pecan pieces over the surface.
Crumble chunks of the reserved cookie dough on top. Again, make the layer even using your fingers.
Bake for about 30 minutes, until golden and mostly set. Allow to cool completely before cutting into squares.