The night before (or at least 8 hours ahead), place the dried 1 lb 干黑豆挑选并冲洗 in a large Mixing Bowl and cover with 3 inches of 8 cups 炖汤用水，另外还需浸泡用水. Let soak overnight at room temperature. Drain and rinse before cooking. (Short on time? See the quick-soak tip in the tips section.)

Add the soaked, drained 1 lb 干黑豆挑选并冲洗 to a large Pot. Add 8 cups of fresh 8 cups 炖汤用水，另外还需浸泡用水, the halved 0.5 洋葱 对半切，一半保持整体用于炖汤，一半切成细丁 half (the whole piece), and 3 whole 5 瓣 大蒜 3 瓣保持整体用于炖汤，2 瓣切碎用于炒 cloves. Bring to a boil over high heat, skimming off any foam that rises to the surface.

Reduce the heat to low, cover partially with a lid, and simmer gently for 1.5 to 2 hours, or until the 1 lb 干黑豆挑选并冲洗 are completely tender and creamy throughout — no resistance when you press one between your fingers. Add 8 cups 炖汤用水，另外还需浸泡用水 as needed to keep 1 lb 干黑豆挑选并冲洗 submerged by at least 1 inch. Add 1 tsp 1 tsp 盐加更多 in the last 30 minutes of cooking.

Remove the 0.5 洋葱 对半切，一半保持整体用于炖汤，一半切成细丁 piece and whole 5 瓣 大蒜 3 瓣保持整体用于炖汤，2 瓣切碎用于炒 cloves and discard. Using a Slotted Spoon, transfer the cooked 1 lb 干黑豆挑选并冲洗 to a large Mixing Bowl, reserving the cooking liquid (bean broth) in a separate container. You'll use this liquid to control the consistency of the final 1 lb 干黑豆挑选并冲洗.

In a large, heavy Skillet (cast iron is ideal) over medium heat, melt the 3 tbsp 猪油或植物起酥油或中性油. Add the diced 0.5 洋葱 对半切，一半保持整体用于炖汤，一半切成细丁 and cook, stirring occasionally, for 5 to 6 minutes until softened and translucent. Add the 5 瓣 大蒜 3 瓣保持整体用于炖汤，2 瓣切碎用于炒, 1 tsp 磨碎孜然, and ½ tsp 干牌鹿蒿，最好是墨西哥牌鹿蒿 (if using) and cook for 1 minute more until fragrant.

Add a large ladleful of 1 lb 干黑豆挑选并冲洗 (about 1 cup) to the Skillet. Use a Potato Masher or the back of a large Wooden Spoon to mash them directly in the pan. Continue adding 1 lb 干黑豆挑选并冲洗 one or two ladlefuls at a time, mashing as you go. This gradual method gives you the best texture and control.

Once all 1 lb 干黑豆挑选并冲洗 are added and mashed to your liking, stir in the reserved bean broth a few tablespoons at a time until you reach your desired consistency — thick and spreadable for a side dish or burrito filling, slightly looser for a dip. Add 1 tsp 辣椒粉 if using.

Continue to cook over medium-low heat, stirring frequently, for 5 to 8 minutes until the 1 lb 干黑豆挑选并冲洗 thicken slightly and pull away from the sides of the pan. Taste and adjust 1 tsp 盐加更多 as needed.

Serve hot, topped with crumbled 2 oz 科蒂哈芝士 碎裂 and fresh 2 tbsp 新鲜香菜粗切 if desired. Great alongside rice, inside burritos or tacos, spread on tostadas, or as a dip with warm tortilla chips.