Katchie Farms makes a tomato jam insanely close in flavor to the one I make, so stock up until tomatoes come into season and you can make it yourself.
1 teaspoon extra virgin olive oil
1 shallot, thinly sliced
1 cup packed baby spinach, well rinsed and dried
1 tablespoon raisins
4 slices, country or white pullman bread
3 tablespoons tomato jam
3 to 4 ounces fresh mozzarella, thinly sliced
Heat olive oil in a small nonstick skillet over medium-low heat. Add the shallots and saute until fragrant, about 1 minute. Add the spinach and raisins and saute until raisins are plump and the spinach is wilted, about 1 to 2 minutes. Remove from heat and set aside.
Heat cast iron skillet over medium flame, or alternately preheat your panini grill.
Meanwhile, arrange two slices of bread on a countertop or cutting board. Slather an equal amount of tomato jam on each slice. Top with equal amounts of mozzarella slices. Arrange equals amounts of spinach on top of cheese. Top with remaining slices of bread.
Place sandwich into hot skillet and use a heavy-bottomed skillet or pot to weight it down, or alternately place it into your heated panini press. If using the manual stovetop method, turn the sandwich once the underside is nicely browned, return heavy-bottomed pot on top of sandwich and continue to cook until golden on other side. Serve hot.