• Melt lard in a double boiler.
• Stirring, dissolve salt and yeast in 100 ml warm water.
• Place the flour on a cutting board. With your fist, make a well in the center of the flour. Pour the lard into the well. Also, add the hot water where you dissolved with salt and baking soda, keeping another 150/200 ml of warm water on hand (depending on how much liquid the flour will absorb).
• Bring the flour toward the center and start kneading, pouring the rest of the water a little at a time. Knead the dough for a long time, even 10-12 minutes, until it is soft and elastic. After 6 minutes of kneading, add the oil and knead quickly to absorb it. 
• Cut out 6 or 8 balls of dough. Roll out the piadina with a rolling pin one at a time. Place the small rolling pin in the center of the ball and start spreading it out. Then, roll the piadina by pushing the rolling pin from the center outward. Gradually cook on the hot aluminum pan for 3-4 minutes per side. When the pan is hot, you may need less time.
• Keep the cooked piadina sealed in a clean dish towel to keep them warm while you cook the others; serve immediately.

Food tips

• Piadina will be fragrant when just cooked, but it will be crispy if you eat it later. Do it this way: brush each piadina with warm water on both sides before heating them on the pan or in the oven. They won't return as fragrant as when made but will regain some elasticity.
• Store in the freezer for one month.