Focaccia is pizza's plain sister...but fluffier! This focaccia is crispy on the outside and chewy on the inside! A perfect vehicle for an afternoon snack or a super sandwich!
In a medium pot, cook 2 1/2 cups water and potatoes until potatoes are fork tender; set aside to cool.
Once cool (about 120 degrees), place potatoes and cooking water into a blender and puree until smooth; set aside.
In a small measuring cup, add the remaining water and heat to about 90-100 degrees (warm) and sprinkle with the yeast; stir well and set aside for 5 minutes.
In a large bowl, mix together flour, sugar and 1 tsp salt; add pureed potato mixture and yeast mixture, mixing well with your hands until mixture is combined. form into a round dough ball and place back into bowl, covering with plastic wrap; set aside for 2-3 hours (or until triples in volume).
Once the dough has risen, take a large rimmed baking sheet (about 13 x 18-inches) and spread the lard/shortening all over the bottom and up the sides. Wit ha rubber spatula, scrape the dough into the prepared baking sheet and press to the edge of the pan; let rest for 1 hour
Set oven to 400 degrees and drizzle the oil over the top of the foccaccia and let sit for 15 minutes; press your fingers into the dough to make "dimples" and sprinkle with salt and rosemary (if using).
Gently place focaccia in the oven (middle rack is best) and bake for 35-40 minutes or until focaccia is golden on the outside.
Cool, slice and enjoy