In a large, heavy bottom sauce pan, saute onion in olive oil over medium heat until soft – about five minutes. Add remaining sauce ingredients, bring up to a simmer, and remove from heat.
When mixture has cooled a bit, taste and adjust salt if necessary. Blend the sauce with an immersion blender until smooth (I just poured the mix into my regular blender and used that… it makes far less of a splattery mess than the immersion blender).
Make the filling:
Preheat the oven to 375°F (190°C).
Start a large pot of water to boil on the stove. Peel potatoes if you like (I leave the skins on for taste and texture) and chop them into 1-inch cubes. Add to potatoes boiling water and boil until tender, about 15 minutes, then drain, mash a bit with a fork, and set aside.
Over a medium-low flame, heat olive oil until it shimmers. Add garlic and cook for one minute, stirring constantly.
Add chard, carrots, and peas, and sprinkle with a little sea salt. Increase burner level to medium, stirring constantly to mix chard, oil, and garlic. Cover and steam for about five minutes, until greens are wilted.
Remove lid and mix in potatoes, mashing a bit more as you go. You want it loose, but with nice potato-y chunks. Add veggie stock, lime juice, cumin, pumpkin seeds, and salt, cooking another four minutes, until the stock is absorbed. Add more stock or lime juice to taste, then remove from heat.
Assemble the enchiladas:
Pour about 3/4 cup of enchilada sauce into a pie plate or deep dinner plate. Create an assembly line in this order: lightly oiled hot cast iron pan for softening tortillas, plate with sauce, filling, and the baking dish where you’ll be putting your finished enchiladas.
Ladle a little sauce into the baking dish and spread it around to lightly cover the bottom. Take a corn tortilla, set it into the hot cast iron pan for 20 seconds, then flip it over and repeat. Once the tortilla is soft and pliable, drop it into the pie plate to completely coat it in sauce, then flip and repeat.
Place tortilla in baking dish and run a generous amount of potato filling down the center, rolling it up and placing it in the dish. Continue with the rest of the tortillas, leaving about a quarter inch between them so that they will be easier to plate.
Pour 1 1/2 cups of sauce over the top of the enchiladas, reserving the rest for later. Cover tightly with foil and bake for 25 minutes, then remove foil and bake for another ten minutes to brown the edges of tortillas.
Allow to cool slightly before serving (they’ll be hot!) and top with a little more enchilada sauce and a dollop of vegan cilantro sour cream.