Place eggs into a small mixing bowl, add dill, water, salt & pepper and whisk until mixed. Heat skillet and add butter. when melted, add spinach and garlic. Stir and cook until spinach is wilted, then spread spinach out in skillet and pour eggs over. Cook over medium-low heat until eggs are mostly set. With a large spatula, flip omelet over briefly to finish cooking eggs. Flip back over, spread cheese over top, cover and cook 1 minute until cheese starts to melt. Fold omelet in half. Slide onto a plate, cut in half to make 2 servings.