To a food processor, add basil and parsley; pulse until finelychopped. (TIP: If you don’t have afood processor, you can finely mince herbs.) Add garlic and salt; pulse to combine. Let mixture sit until liquidsrelease, about 5 minutes.Transfer herb mixture to an 8-oz wide-mouth glass jar. Using aspoon or your hand, press mixture down firmly to release liquid and remove any air pockets, pressing until ingredients are completely submerged and leaving 1 inch head-space between herb mixture and rim of jar.Arrange cabbage leaf directly over top of herb mixture to keep herbssubmerged in liquid; seal loosely with lid.Let ferment in a cool place away from direct sunlight, pressing down on cabbage every 24 hoursor as needed to keep herb mixturesubmerged in liquid, for 5 to 10 days.(TIP: Begin tasting on day 5 andcontinue to ferment until mixture reaches desired acidity.)Discard cabbage leaf and top pesto with waxed paper. Seal tightly with lid and refrigerate for up to 12 months.