Yes, you can make steak quesadillas in the oven. That said, they won't get as crispy as they will in a pan on the stovetop, but it's great when you are cooking for a large group. To do so, assemble the quesadillas in a single layer on a baking sheet and cook them for 5 minutes at 400°F on one side. Flip them over and cook them for 5-6 more minutes on the other side.