Line a half-sheet rimmed baking tray with parchment. Set aside.

In a large round bowl, sift together bread flour and unsweetened cocoa powder.

Add the lukewarm water, olive oil, granulated sugar, kosher salt, instant yeast, and vanilla extract. With a bench scraper, bring the ingredients together until a soft dough forms.

Turn dough out onto a lightly floured countertop and knead by hand until soft and elastic, about 8-10 minutes.

Knead in the chopped dark chocolate.

Shape dough into a ball and place in a well-oiled bowl. Drizzle with additional oil.

Allow bowl to stand in a warm place, covered, for about 1 1/2 – 2 hours, or until dough doubles in size.

Punch dough down. Place on prepared tray and shape into an 8-9-inch circle.

Cover tray with clingfilm/plastic wrap, then place a kitchen towel on top. Allow dough to prove until doubled in size, about 1 hour more.

Preheat oven to 400° F / 205° C.

Peel away the plastic wrap. With a pastry brush, brush dough generously with olive oil.

Add the cranberries, chopped dark chocolate, and rosemary pieces, covering most of the surface. With your fingers, push the toppings down to create deep dimples in the dough.

Drizzle remaining 65 milliliters (1/3 cup) olive oil over dough, allowing it to fill the dimples. Sprinkle with flaky sea salt.

Bake in preheated oven for 30 minutes, or risen and fully set.

Brush with more oil. Slice with a serrated knife. Serve warm or at room temperature.

Wrap leftover focaccia in foil or transfer to an airtight container. Store at room temperature for up to 1 day.