Activate the Yeast: Combine warm water and sugar in a stand mixer, whisk until dissolved. Sprinkle yeast over top and let sit for 5 minutes until foamy.

Prepare the Dough: Add bread flour, all-purpose flour, and salt; mix on low until sticky dough forms (2-3 minutes).

First Rise: Grease a bowl with olive oil, transfer dough and coat with oil. Cover and let rise for 1 hour until doubled in size.

Shape the Dough: Grease a 9x13 pan, transfer dough, folding in thirds. Cover and let rise for another hour.

Preheat and Prepare for Baking: Preheat oven to 425°F. Poke dimples in dough, drizzle with olive oil, and spread raspberry jam into dimples.

Bake the Focaccia: Bake for 18-22 minutes until lightly golden.

Poke and Fill with More Jam: Let cool slightly, poke additional holes and fill with more raspberry jam if desired.

Make the Icing: Mix powdered sugar and milk until smooth. Adjust with more milk if necessary.

Ice and Serve: Drizzle icing over cooled focaccia and serve immediately.