Put the molasses, brown sugar, butter and lard in a pot and heat, stirring constantly under medium-low heat until the butter, lard and sugar are completely melted. DO NOT BOIL. The process can be sped up by first softening the butter and lard in the microwave. Do not allow the mixture to scorch, or the cookies will not hold together.
Take the mixture off the heat and add 2-1/2 cups of flour, along with all of the spices. Mix thoroughly and set aside to cool to lukewarm, stirring occasionally.
Lightly beat the eggs and incorporate them into the dough. Let it cool completely.
Sieve together the remaining flour with the baking soda and baking powder. Add the flour gradually to the dough, stirring thoroughly after each addition. When the dough becomes too thick to stir, knead with your hands -- first in the bowl, then on a well-floured work surface. Initially the dough will stick like glue, but eventually you will get a smooth, shiny and quite heavy dough. Add more flour if needed, but only a bit at a time.
Grease a bowl with butter and put the dough in it. Cover with cloth and let rest for a couple of hours.
To bake: Generously flour your work surface. Take a piece of dough and roll it out very thinly. Cut out shapes and place on a cookie sheet. No need to grease the sheet -- that's why the lard is there (you won't taste it at all).
Bake in a 400 degree oven. The cookies should bake in no more than five or six minutes -- watch them carefully, and when the bottom edge begins to brown and the surface looks dry, they should be ready. Take the cookies out of the oven and put the pan on a rack. When the cookies cool, they should be harder and slide off the pan. If they are still moist or stick, pop them back into the oven for another minute or two.
This recipe makes lots of cookies, so it can be halved (or doubled, for that matter). The dough will keep almost indefinitely in the fridge, covered with plastic wrap. When it comes out of the fridge, it will be quite hard, but a bit of kneading and rolling will make it soft and pliable again.