Spinach and Feta Grilled Cheese | Kitchn

Heat 1 tablespoon of the olive oil in a large nonstick skillet over medium-high heat until shimmering. Add the lemon slices in a single layer and sear until dark golden brown, 2 minutes per side. Transfer to a cutting board and finely chop.Add 10 ounces baby spinach and 1/4 cup water, and scrape up any browned bits from the bottom of the pan. Toss until the spinach is almost wilted, about 2 minutes. Crumble in 8 ounces feta cheese with your hands and toss until the feta is warmed through and starting to melt, about 2 minutes. Taste and season with kosher salt and black pepper as needed. Transfer the mixture to a bowl (reserve the pan).Place the ciabatta(s) cut-side up on a baking sheet. Broil until golden brown and toasted, 1 to 2 minutes. Divide 4 ounces of the sliced mozzarella cheese onto the bottom halve(s) of the bread. Divide and spread the spinach mixture evenly over the mozzarella. Top with the red peppers and remaining 4 ounces mozzarella. Close the sandwiches with the top halve(s) of the bread.Wipe out the reserved skillet. Cut the sandwich in half if needed to fit into the skillet. Melt 2 tablespoons unsalted butter in the skillet over medium-low heat. Add the sandwich(es). Cover (it’s ok if the lid doesn’t fit perfectly, as long as it is partially covering the sandwich) and cook until the bread is golden brown and the cheese is melted, occasionally gently pressing down on the sandwich(es) with a rubber spatula, about 5 minutes per side.