Seitan and Polenta Skillet with Fresh Greens - Vegetarian - Kosher Recipe

Ingredients

• One 18-ounce tube polenta
• 1 ½ tablespoons olive oil
• Cooking oil spray, optional
• 1 tablespoon reduced-sodium soy sauce
• 1 pound seitan, cut into bite-size pieces or strips
• 4 large or 6 medium stalks bok choy, with leaves, sliced crosswise
• 5 to 6 ounces fresh baby spinach
• 4 scallions, sliced
• 1 tablespoon balsamic vinegar, or more to taste
• ¼ cup sliced oil-packed sliced sun-dried tomatoes, optional
• Salt and freshly ground pepper to taste