In a mixing bowl, combine warm water and sugar. Whisk to dissolve, then add yeast and let sit for 5 minutes.

In a stand mixer, combine the yeast mixture with bread flour, all-purpose flour, and salt. Mix until a sticky dough forms, then mix for 5 minutes.

Grease a large bowl with olive oil, transfer the dough, cover, and let rise for about 1 hour.

Grease a 9x13 baking pan with olive oil. Punch down the dough and transfer to the pan, stretching it. Cover and let rise for another hour.

Preheat the oven to 425°F. Poke dimples in the dough and spoon raspberry preserves into each one.

Bake for 18-22 minutes until golden brown. The edges should be crisp, and the center soft.

Poke more holes in the focaccia once removed from the oven and fill with more raspberry preserves.

Mix confectioners' sugar with milk for glaze and drizzle over the focaccia.

Cut into generous squares and serve warm.