Preheat the oven to broil. Place the poblano peppers on a foil-lined cookie sheet and broil on high for about 5 minutes until the exposed sides are blackened. Flip them over and broil for 5 minutes. Remove them from the oven and wrap the poblanos in the foil from the cookie sheet. Set them aside so they can steam while you make the filling.
Coarsely chop the chickpeas, lentils and walnuts in a food processor. Be careful not to overchop. Saute the onion in a pan over medium heat with 1/2 cup (118ml) of veggie broth and 1/4 teaspoon of salt until it begins to soften, about 4 to 5 minutes. Add the garlic and saute for about 1 to 2 minutes until the garlic is browned. Add the bean/nut mixture and saute for 2 to 3 minutes until it begins to dry, then add 2 cups (480ml) of broth, tomatoes, cumin, oregano, 1 teaspoon of salt, chili powder and pepper. Cook partially covered for about 20 to 25 minutes until the beans are cooked and the liquid has mostly evaporated. Stir frequently, and lower the heat if it begins to stick, which can happen if you are not using oil. Uncover when most of the liquid has evaporated and continue to cook, mixing frequently until the liquid is almost gone. Set aside.
Preheat the oven to 400°F (204°C). Remove the poblanos from the foil and carefully remove the skins. Gently cut a slit in each one, and remove the stem and seeds. Place each poblano on a tortilla opened and lying fat, put about one-fifth of the meaty bean/nut mixture and a spoonful of cream sauce in the pepper and then fold the pepper closed.
To fold the burrito, fold the sides over toward the center and above the stuffed poblano, then roll upward to create a burrito with the pepper stuffed inside. Place the burritos on a parchment-lined baking sheet and bake for about 20 minutes. Carefully flip them over using a spatula and bake for 5 minutes until they're crisp.
Remove them from the oven and top them with more cream sauce and the roasted salsa (of your choice). Sprinkle them with green onions and cilantro if desired (either before or after baking again). Bake for 5 to 7 minutes until the sauces are hot. Serve immediately!
For the cream sauce, put the potato, milk, cashews, broth, wine, vinegar, lemon juice, garlic and salt into a high-speed blender and puree until smooth. Refrigerate the sauce to thicken.
Notes regarding the sauce: Cook the potato in the microwave or oven. I don't recommend boiling it because it makes the potato too wet.
If you are not using a high-speed blender, there are a couple of options for making your sauce smooth. You can use a coffee grinder to grind everything to a fine powder, or make sure to soak your cashews overnight, or for at least 2 to 3 hours. If you forget, you can also boil them for 30 minutes. You can easily substitute the water for the broth, however the broth gives it a nicer flavor. Wine is recommended for the ultimate flavor, but if you don't want to use wine, feel free to replace it with more broth. Adjust the amount of broth depending on how thick you want the sauce.
Kids: This can be served as a bowl if folding a burrito is too hard!