2/3 cup chickpea flour (also known as garbanzo bean flour)
1/2 tsp fine sea salt
3 tbsp extra virgin olive oil
Needles from a small sprig of fresh rosemary
Kosher salt & freshly ground black pepper
1-2 oz fontina cheese and/or prosciutto, cut into slivers
Combine the flour with 3/4 cup water in a bowl & use a metal whisk until it is smooth. Whisk in the sea salt & 2 tbsp of the olive oil. Let sit at room temperature for at least 4 hours.
Preheat the oven to 450°F.
Swirl the remaining 1 tbsp of olive oil in an 11" cast-iron or ovenproof nonstick skillet. Place in the hot oven for 10 minutes.
Pour all of the butter into the hot pan & swirl so that the batter reaches up the pan by 1/4". Scatter the rosemary on the surface & bake for 15 minutes, or until the lacy edges begin to darken & the underside is golden.
Immediately sprinkle with a pinch of kosher salt & plenty of pepper. Slide the pancake onto a cutting board. Top with the fontina and/or proscuitto, cut into eighths, & serve hot.