Recipe for Pansotti Filling

I cooked fresh pansotti with walnut sauce using the recipe at https://www.the-pasta-project.com/pansotti-pasta-with-walnut-sauce-recipe-from-liguria/#recipe . The dish turned out pretty good, but I felt the filling was a little bland and flavorless. I followed the recipe closely with the exception that I was not able to obtain radicchio and therefore added additional spinach and chard.

Next time I make pansotti I'm going to add extra salt and pepper to the filling. But does anyone else have recommendations to make the filling tastier?

Thanks.