Place the corn husks in a heatproof bowl. Cover with boiling water and let soak for at least 30 minutes to make them pliable.
In another bowl, stir 2 cups hot water into the masa harina. Beat with a wooden spoon until completely blended. Set aside for 30 minutes to cool.
Dissolve the baking soda and salt in 1 cup water. In a bowl with an electric mixer, beat the lard and baking soda mixture together until well blended and thick, or until it looks like mayonnaise.
With the mixer on, add the masa dough by handfuls until completely blended.
In a bowl, combine the pumpkin, cheese, epazote and chile.
Place a corn husk on a work surface with the wide end facing you. Spread 3 tablespoons of the masa mixture over the wide end of the husk, leaving a 1-inch margin at the bottom and at least a 1-inch margin on the two sides.
Place 1 generous tablespoon of the pumpkin mixture down the center of the masa. Bring up the two long sides of the husk to force the masa to enclose the filling, then roll up tightly the long way.
Fold down the narrow tip to meet the wide bottom edge. The packet should stay closed on its own, but some cooks choose to tie it closed with a strip of corn husk.
In a vegetable steamer or a steamer insert for a spaghetti pot, pack in the tamales open end up. Steam for 1 hour.
The tamales are done when the husk can easily be peeled off. Replenish the boiling water as necessary.
Let the tamales sit for 10 minutes before serving.