In a stand mixer bowl, combine 1 3/4 cups of warm water with 2 teaspoons of sugar, whisking gently to dissolve. Sprinkle in 1 packet of active dry yeast and allow to sit for 5 minutes until bubbly.

Attach the dough hook and add 2 cups of bread flour, 2 cups of all-purpose flour, and 2 teaspoons of salt. Mix on medium speed until a sticky dough forms, about 5-7 minutes.

Transfer the dough to a lightly oiled bowl, cover with plastic wrap, and place in a warm spot for about 1 hour, until doubled in size.

Grease a 9x13 baking pan with olive oil. After the first rise, punch down the dough and move it into the prepared pan, pressing down to cover the bottom.

Preheat your oven to 425°F. Use fingers to poke deep dimples in the surface of the risen dough for filling with raspberry preserves.

Bake the focaccia for 18-22 minutes until golden brown; toothpick should come out clean.

Remove from oven, let cool briefly, then poke additional holes and fill with raspberry preserves.

Mix 2 cups of confectioners' sugar with 2-4 tablespoons of whole milk for glaze consistency, and spread it over the focaccia.

Allow to set briefly before cutting into squares. Serve warm or at room temperature.