Heat a fireplace to medium heat. Adjust the grill
racks over the flame and heat a heavy Dutch oven
over the rack. Alternatively, heat a medium saucepan
over medium heat.
Once hot, add the oil to the saucepan. Add the pancetta and render
some of its fat. Add the rosemary and garlic, and saute until fragrant. Stir in the beans, lemon juice
and some salt and pepper. Mash the beans with the back of a wooden spoon. Don't mash
them all smooth, you want some texture.
Toast the baguette
slices. Serve the beans on top of the toasted baguette. Drizzle
with olive oil if desired.