Place the basil leaves in a food processor and pulse 3-4 times until roughly chopped.
Add in the garlic cloves and pulse 3-4 more times.
Add <g class="gr_ gr_104 gr-alert gr_gramm gr_run_anim Grammar only-del replaceWithoutSep" id="104" data-gr-id="104">in </g>the walnut pieces and again pulse 3-4 more times until roughly combined.
With the food processor running on low, stream in the olive oil followed by the vegetable broth until well combined.
Stop the food processor, remove the top and scrape down the sides.
Add <g class="gr_ gr_105 gr-alert gr_gramm gr_run_anim Grammar only-del replaceWithoutSep" id="105" data-gr-id="105">in </g>the parmesan cheese, salt and pepper and process on high until a loose spread forms and the ingredients are well combined.
Store in an airtight container in the refrigerator for 3-5 days or freeze until ready to use.