Combine 500 g T45 wheat flour and 8 g dry yeast in a large mixing bowl.

Pour in 300 ml water and mix until no dry flour remains.

Add 8 g salt and 15 ml extra virgin olive oil to the dough.

Knead the dough for 8 to 10 minutes until smooth and elastic.

Cover the dough and let it rise at room temperature for 90 to 120 minutes, until doubled in size.

Strip the rosemary, thyme, savory, and sage leaves from their stems and roughly chop them.

Pound the chopped herbs, 1 garlic clove, and 0.3 g salt in a mortar until a coarse paste forms.

Gradually work 100 ml extra virgin olive oil into the herb paste until the pistou is spoonable.

Peel the butternut squash and cut it into thin half-moon slices, about 3 mm thick.

Bring a large saucepan of salted water to a boil.

Blanch the butternut squash slices for 2 to 3 minutes until barely tender, then drain thoroughly.

Preheat the oven to 280 °C (535 °F) with a baking surface inside.

Divide the risen dough into 4 equal portions and shape each portion into a ball.

Roll each dough ball into a small disc about 18 cm wide, leaving the outer edge slightly thicker.

Spread 50 g ricotta over each dough disc, leaving a 1 cm border uncovered.

Spoon the pistou over the ricotta, using about one quarter of the pistou per pizzetta.

Arrange one quarter of the blanched butternut squash slices over each pizzetta.

Bake the pizzettes for 5 to 6 minutes at 280 °C (535 °F) until the edges are puffed and deeply golden.

Serve the pizzettes hot while the crust is crisp and the ricotta is warm.