In a stand mixer, combine warm water and sugar, stirring until dissolved. Sprinkle in active dry yeast and let sit for 5 minutes until bubbly.

In a separate bowl, whisk together bread flour, all-purpose flour, and salt. Once yeast is active, add dry mixture to the stand mixer and mix on low speed for 2-3 minutes until sticky dough forms.

Lightly grease a large bowl with olive oil, transfer the dough, and cover with plastic wrap. Let rise in a warm place for about 1 hour or until doubled in size.

Grease a 9x13 metal pan with olive oil and transfer the dough, folding it lightly. Cover with a clean towel and let rise for another 30 minutes to 1 hour until puffed.

Preheat oven to 425°F. Poke holes all over the risen dough with your fingers, then spoon the raspberry jam into each dimple.

Bake the focaccia for 18-22 minutes until golden brown. Let cool slightly after removing from the oven.

Prepare the glaze by mixing powdered sugar with milk until smooth. Poke more holes in the cooled focaccia and drizzle the glaze over the top.