Preheat oven to 400°. Place tomatoes, onions, olive oil and salt onto baking sheet and mix well. Place on center rack in the oven and roast for 20 minutes. Remove from oven and let cool.
Slice the chiles down the center and remove stems and seeds. Place onto a dry baking sheet and bake for 2–3 minutes at 400° until fragrant, being careful not to burn. Remove from oven. Place beef stock in a saucepan and heat without boiling. Remove saucepan from heat. Add chiles to the stock and allow to soften for 30 minutes. Remove chiles to a bowl and save all the liquid.
Cook tamales in their sealed package in boiling water for 45 minutes. Remove from package and set aside.
Place tomato/onion mixture, garlic, cumin, 2 Tablespoons chili-infused beef stock, salt and reconstituted chiles into food processor or blender and blend until very smooth. Add more stock to obtain desired consistency.
Place a small amount of sauce on top of your tamales and top with a dollop of sour cream.
Recipe by Village Farms at https://staging-villagefarmsn.kinsta.cloud/recipes/cabernet-estate-reserve-tamale-recipe