In a small bowl, combine warm water with sugar, whisking until dissolved. Sprinkle yeast and let sit for 5 minutes until frothy.

In a larger bowl, combine bread flour, all-purpose flour, and salt. Pour in the yeast mixture and mix until a sticky dough forms.

Transfer dough to a greased bowl, cover, and let rise in a warm place for about 1 hour or until doubled in size.

Grease a 9x13-inch baking pan with olive oil. Punch down the risen dough and stretch it into the pan.

Cover with a towel and let rise again for 30-60 minutes.

Preheat oven to 425°F.

Drizzle olive oil over risen dough and poke deep holes into the surface. Fill holes with raspberry preserves.

Bake for 18-22 minutes until golden brown and hollow-sounding when tapped.

Remove from oven, poke additional holes, and fill with more raspberry preserves.

Whisk confectioners' sugar with whole milk to create the glaze and drizzle over cooled focaccia.