If using fresh Masa, set aside. If using Masa Harina, place it in a large bowl and reconstitute by adding 4 cups warm stock. Beat with a wooden spoon or mix with your hands until you have a stiff, smooth dough like a medium-pliable bread dough. Use a little more stock if necessary, but the mixture should not be loose. Beat the lard in a large bowl with an electric mixer on medium speed until very fluffy and fully aerated, about 3 minutes. It may take longer if your mixer is not powerful (a heavy-duty machine such as a Kitchen Aid is best). The best alternative to a mixer is not a spoon but your bare hand; whip and beat the lard with a rapid folding motion until you feel it lightening, and continue to whip until it is fluffy and full of air. It should be as light as butter creamed for the lightest butter cake. Still mixing on medium speed, begin adding the Masa, a handful at a time. Stop to scrape down the sides of the bowl with a rubber spatula as necessary. Alternatively, beat in the Masa using your bare ha nd as a whipping and folding tool. If the mixture becomes too stiff to beat, add up to 1 cup tepid chicken or pork stock, a little at a time. When all the Masa has been incorporated, the mixture should be very light and delicate, the texture of buttercream frosting. Beat in the salt. The mixture is now ready to be spread onto corn husks, banana leaves, or other wrappers and steamed