Preheat your oven to 170°C / 340°F and take the lard out of the fridge. It needs to be at room temperature so you can work with it later.
Spread the flour on a baking sheet and put it in the oven to dry out for 30 minutes. Mix it from time to time so it doesn't catch.
While the flour is drying out pour boiling water over the almonds and leave them in there for 2-3 minutes. Drain and pour cold water over them. That way the skin will come off easily. Peel the almonds and spread evenly on a baking sheet. Place them in the oven for 10 minutes. Have an eye on them. You want them to brown just a tiny bit, but not too much or else they will turn bitter.
When the almonds are toasted, take them out the oven and leave them to cool down. When cold grind them in a food processor.
In a big bowl sift in the flour and 250g of the sugar. Add the almonds and the cinnamon and mix well.
Cut the lard into small pieces and add to the bowl. Work the dough with your hands until it all comes together. It might seem impossible in the beginning, but after a while a dough will form.
Set your oven to 200°C / 392°F fan.
On a worktop roll out the dough around 1cm thick.
Cut out 6x4,5cm ovals (or rounds or whatever shape you want really...) and place them on a baking sheet.
Bake for 15 minutes.
Take the polvorones out and leave them to cool off completely or else they will fall apart when you touch them.
When they are cold and firm, coat each one in confectioners' sugar and wrap in silk paper.