Preheat oven to 350°F.
In a larger skillet, sauté greens until tender and wilted.
Spread pesto evening on one side of the bread. Layer on artichoke hearts, greens and grated cheese and top with remaining bread slices.
Heat an oven-proof skillet to medium heat and lightly coat the tops of the sandwiches with butter. Cook sandwiches until golden brown on each side, about 2 to 3 minutes. Finish in the oven for another 2-5 minutes until cheese is gooey and melted.