Stir together flour, sugar, baking powder, salt, and raisins in a large bowl until evenly blended. Whisk together milk, molasses, and vanilla extract in a separate bowl, and set aside. Use your hands to work the melted lard into the flour mixture until coarse and crumbly. Mix in the molasses mixture until a wet, sticky dough is achieved.
Place a heatproof ceramic plate in the bottom of a large pot and fill with water. Bring to a boil over high heat.
Scrape dough into the center of a clean, 2x2 foot cotton cloth. Bring the corners and sides of the cloth around the dough, and tie the pouch closed with strong kitchen twine, leaving about 1 1/2 inches of room for the dough to expand at the top.
Carefully place dumpling into boiling water, making sure it is immersed. Cover, and return to a boil. Reduce heat to medium-low, and simmer gently for 3 1/2 hours.
After 3 1/2 hours, carefully remove dumpling from the simmering water, and remove the cotton cloth. Place onto a plate and allow to cool. Serve warm or cold.