Heat a camping stove or grill to medium-high (about 375° to 400°F), or fit a grilling grate over the direct heat of glowing embers. Cut or tear a 16- x 14- inch rectangle of heavy-duty aluminum foil. Place the cream cheese in the center of the foil; top with the mayonnaise, onions, and Gruyere. Bring the long sides up and over the cheese mixture; double- fold the top and sides of the foil, and tightly seal.
Place the foil packet on the camping stove or grilling grate, and cook until the cheeses are melted, 10 to 15 minutes. Remove from the heat; open the foil, and stir to combine. Sprinkle with the pepper. Serve immediately with the bagel crisps or grilled bread.
Hands-On: 15 minutes
Total Time: 1 hour
Serving Size: Makes 2 cups
Heat 2 tablespoons olive oil in a medium skillet over medium-low. Add 4 cups thinly sliced sweet onions (about 16 ounces) and 1 ½ teaspoons chopped fresh thyme; cook, stirring occasionally, until the onions are very soft and golden brown, about 35 minutes. Add 1 tablespoon apple cider vinegar and ¼ teaspoon kosher salt, stirring and scraping the browned bits from the bottom of the skillet. Remove the skillet from heat, and cool the onions to room temperature, about 10 minutes. Roughly chop the onions, and store in an airtight container for up to 1 week.