Kale and Caramelized Onion Grilled Cheese with Roasted Poblano-Tomato Soup

4 medium kale leaves, stems removed

2 teaspoons canola oil

2 medium red onions, cut into 1/2-inch-thick slices

1/4 teaspoon freshly ground black pepper

1/8 teaspoon kosher salt

1 teaspoon red wine vinegar

8 (1-ounce) slices multigrain bread

Butter for pan

1 ounce finely grated Parmesan cheese, divided (about 1/4 cup)

3.5 ounces shredded raclette or Gruyere cheese (about 7/8 cup)

Preheat oven to 300°.

Bring a small pot of water to a boil; add kale. Remove from heat; let stand 4 minutes or until kale is bright green. Drain; rinse kale under cold water until cool. Pat leaves dry and tear into small pieces.

Heat a skillet over medium-high heat. Add oil; swirl to coat. Add onion, pepper, and salt. Cook 10 minutes or until onion is tender and browned, stirring frequently. Remove from heat; stir in vinegar, tossing to coat.

Heat a large nonstick skillet over medium heat. Lightly butter the pan, then place bread on the butter and top with cheese, kale, onions, more cheese, and another slice of bread. Work in batches to create all four sandwiches. Transfer the sandwiches to a cookie sheet and bake at 300° for 5 minutes or until cheese melts.