In a stand mixer, combine warm water and sugar. Whisk until dissolved. Add the active dry yeast and whisk until combined. Let sit for 5 minutes.

Attach a dough hook to the stand mixer. Add bread flour, all-purpose flour, and salt. Mix until a sticky dough forms.

Spread 2 tablespoons of olive oil around the sides of a large mixing bowl. Place the dough into the bowl and coat it with oil. Cover with plastic wrap and let rise in a warm place for 1 hour.

Once the dough has doubled in size, spread 2 tablespoons of olive oil around a 9×13 metal pan. Remove the dough from the bowl and place it in the pan. Fold in thirds a few times, coating with oil.

Cover the pan with plastic wrap and let the dough rise for another hour.

Preheat the oven to 425°F. Remove the plastic wrap and pour the remaining 2 tablespoons of olive oil onto the dough. Poke holes throughout the dough with your fingers.

Spread ¼ jar of raspberry jam onto the unbaked focaccia dough.

Bake for 18-22 minutes until lightly golden brown.

Use a straw to poke holes into the bread and scoop jam into each hole.

Once slightly cooled, mix powdered sugar with milk to make icing. Frost the focaccia with icing and cut into squares.