Using oil, spray, or butter, generously grease a 13” x 18" rimmed baking sheet. (13" x 18" is best for a thin snacking focaccia, but you can use a 9" x 13" baking pan as well.)
Turn the dough out onto the prepared baking sheet, and gently fold and knead it 3 times, then press it into the corners of the baking sheet. (Since the dough stretches, sometimes it's hard to get it fully in the corners at this point, but the second rise will help shortly.)
Using a spoon, roughly spread ⅔ of the raspberry jam evenly over the flattened dough. Oil your hands and then fold the dough into thirds from the short side. Turn the dough so the long side matches the long side of the pan.
Allow to rise 1½ - 4 hours uncovered in a warm, dry spot.
Coat your hands in olive oil and stretch the dough into the corners of the pan. Dimple the foccaccia all over with your fingers. Make several pockets on top and add dollops of the remaining raspberry jam.
Bake 20-30 minutes until golden all over.