1. Heat 1 tablespoon butter and the garlic in a large pot over medium-high heat. Add greens, and cook, stirring often, until wilted, about 3 minutes. Stir in stock, 3/4 teaspoon salt, 1/8 teaspoon pepper, and the zest, and cover. Reduce heat to medium, and cook until tender, 8 to 10 minutes. Add lemon juice and remaining tablespoon of butter. Stir until butter melts. Season with salt and pepper, and serve immediately with lemon wedges.