Step 1: The day before you are ready to assemble the tamales, start your meat filling by seasoning each roast well with salt and pepper. In a hot Lodge cast-iron skillet, sear each roast for 2 to 3 minutes per side to brown the surface of the meat.
Step 2: Move both roasts to the slow cooker. Add green chile peppers, onion, garlic, chipotle peppers, broth and a tablespoon each of salt and pepper. Cook on low for at least 12 hours.
Step 3: An hour before assembling the tamales, place the dried corn husks in a pan and cover with hot water. Cover the pan and allow the husks to soak and soften.
Step 4: Heat 3 inches of water in a medium sauce pan to boiling. Remove from heat and add the dried ancho peppers. Cover the pan and allow the peppers to soak for 30 minutes.
Soak the dried ancho chili peppers in hot water until soft.
Once the peppers are soft, remove the stems and seeds. Add the soft peppers to a food processor or blender and process to a smooth paste.
Remove the seeds and stems from the softened ancho peppers before grinding them.
Pour the pepper paste into a wire strainer and push the paste through with a spatula into the cooked meat filling. Use forks or tongs to thoroughly mix the ancho sauce into the filling.
Push the ancho pepper pulp through a wire strainer into the cooked venison and pork.
Step 5: Add the masa flour to the bowl of a mixer. Using the dough hook or paddle, start blending in the dry ingredients, then add the lard and butter. Once the fat is blended into the flour, start adding the stock, and then the water, reserving the final cup of water. Blend the mixture thoroughly, with the goal being the consistency of smooth peanut butter. If the mixture is to dry, slowly add some of the reserved cup of water until you reach your desired smoothness.
Step 6: To assemble the tamales, remove the husks from the water and pat them dry with a clean cloth or paper towel. Spread a corn husk on your work surface and spoon an egg sized ball of dough onto the upper (wide) portion of the husk. Spread the dough evenly over the upper two thirds of the husk, leaving one edge and the bottom third uncovered.
Cover the upper two thirds of the husk with a thin layer of masa dough and spoon on some meat.
Spoon a heaping tablespoon of the meat filling onto the dough, spreading it in a line from top to bottom of the dough-covered area. Start rolling the tamale from the dough-covered side toward the empty side of the husk. Once the tamale has been rolled, fold the tail end of the husk up onto the filled portion. Move the rolled tamale to a pan while you continue rolling the remainder of the tamales.
Continue rolling the tamales until all the meat has been used.
Step 7: To steam the tamales, place them into a large pan with a wire rack or stainless colander inside. Add water up to the base of the rack or colander. Stack the filled tamales vertically to fill the pot. Cover the pot with a tight-fitting lid and place over medium-high heat until the water comes to a boil. Turn down the heat to medium and continue steaming the tamales for two hours.
Steam the tamales in a large pan on either a wire rack or stainless-steel colander.
Step 8: To serve, unwrap the corn husk from the warm tamale. I like to top the tamales with red enchilada sauce and sour cream.
Step 9: Pack any leftover tamales into single or family sized servings inside a vacuum sealed bag and freeze.