In a small bowl, combine warm water with sugar and whisk in active dry yeast. Let it sit for about 5 minutes until bubbly.

In a stand mixer, combine the yeast mixture, bread flour, all-purpose flour, and salt. Mix on low speed until a sticky dough forms (3-4 minutes).

Transfer the dough to an oiled bowl, cover it, and place in a warm spot to rise until doubled in size (about 1 hour).

Grease a 9x13 inch baking pan. Transfer the dough, shape it, and cover it to rise again for another hour.

Preheat your oven to 425°F (220°C).

Poke deep holes into the dough and spoon raspberry preserves into these holes to fill them.

Bake in the preheated oven for 18-22 minutes until golden brown. Cool slightly in the pan.

Whisk together confectioners’ sugar and milk until smooth. Spread over the cooled focaccia and allow to set.