Spread chipotle ranch on all four slices of sourdough bread. Assemble pastrami, tomatoes, and cheese into sandwiches.

Preheat skillet or grilling pan over medium heat. Spray it with a nonstick cooking spray. Add both sandwiches to the pan. Lay a heavy pan on top to weigh it down. You may also place something inside the pan to add extra weight. Cook until golden and crisp, 3 to 4 minutes per side.