In a stand mixer bowl, combine 1 ¾ cups of warm water and 2 teaspoons of sugar. Whisk until dissolved, then sprinkle in 1 packet of active dry yeast. Let rest for 5 minutes.

Attach a dough hook and add 2 cups of bread flour, 2 cups of all-purpose flour, and 2 teaspoons of salt to the bubbly yeast mixture. Mix until a sticky dough forms.

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

Gently deflate the dough, place in a greased 9x13 baking pan, fold to develop texture, cover, and let rise again for 1 hour.

Preheat oven to 425°F (220°C). Poke deep dimples in the dough and spread raspberry preserves into each dimple.

Bake for 18-22 minutes until golden brown. The aroma will signal that it is nearly ready.

Poke additional holes after baking to allow more preserves to seep in. Let cool in the pan for 10 minutes.

In a bowl, mix 2 cups of confectioners' sugar with 2-4 tablespoons of whole milk until smooth for icing.

Spread icing over cooled focaccia and cut into squares for serving.