Soften the lard at room temperature. Beat the eggs in a bowl, add the sugar and continue beating with a fork. Put the baking soda in the yoghurt and let it bubble. Then add it to the bowl. Add the lard as well. Put the baking powder in 1 cup flour and stir. Add the flour to the bowl and stir with a spoon.
Gradually add more flour to obtain a sticky, thick dough. Once it becomes impossible to stir with a spoon and barely comes off the walls of the bowl, add a little more flour and finish kneading the dough. Eyeball the amount of flour you need to obtain a sticky, thick, soft dough. You have to be unable to roll it out.
With oiled hands, form equal-sized balls and arrange them in a tray laid out with baking paper. Sprinkle each ball with sugar. Bake in a preheated 356°F (180 °C) oven. It needs to be preheated in order for them to puff up and swell. The cookies end up cracked and very tasty.
The products listed yield 30-34 cookies. The lard makes them crumbly and really delicious. Homemade white lard and free-range eggs are best!