Hot sandwiches with cheese, spinach and artichokes

Ingredients:

• 1 small red onion, quartered and thinly sliced
• 1/4 cup apple cider vinegar
• 2 tbsp extra-virgin olive oil + extra for greasing
• 1 can (400g) canned artichoke hearts, drained and coarsely chopped
• 1 package (140 g) baby spinach (about 8 cups)
• 1 tbsp. grated Asiago cheese (about 110 g)
• 1/3 cup crumbled goat cheese (about 60 g)
• 1/4 cup mayonnaise
• 8 slices of bread with 2 cm thick crust.
• 2 cups small tomatoes, such as Campari, quartered
• 1/4 cup coarsely chopped fresh parsley

Preparation:

1. Combine half the onion, vinegar, and a pinch of salt in a medium microwave-safe bowl. Microwave until hot; set aside.
2. In a large skillet, heat the olive oil over medium-high heat. Add the remaining onion and cook, stirring, for 3 minutes. Add the artichokes and cook for 4 minutes. Add half the spinach and cook until wilted, another 2 minutes. Remove from heat and stir in the Asiago, goat cheese, mayonnaise, and remaining spinach.
3. Preheat a grill pan over medium heat. Make sandwiches with the spinach and artichoke mixture. Brush the bread with olive oil and place in the grill pan. Grill for 3 minutes on each side. Let the sandwiches rest for 2 minutes; cut in half.
4. Drain the onions. Drizzle with olive oil, then add the tomatoes, parsley, and salt and pepper to taste; toss to combine. Serve the salad with sandwiches.