In a bowl, combine the bread flour, all-purpose flour, pumpkin puree, olive oil, fine salt, and active dry yeast. Mix with a spoon, then knead by hand until the dough is smooth and even.

Cover the bowl with plastic wrap and a towel. Let the dough rise for at least 4 hours.

Once the dough has risen, grease your fingertips and spread the dough onto a baking sheet lined with parchment paper.

Sprinkle coarse salt and rosemary on top. Cover with plastic wrap and let rise for another hour.

After rising, bake in a preheated oven at 400°F (200°C) for about 30 minutes, or until golden brown.