Combine all of the ingredients in a blender and process until smooth (or whisk the ingredients together in a medium bowl until smooth).
Griddle Cooking: preheat an electric griddle to medium heat (about 325 to 350 degrees F). Brush griddle with melted butter. Pour 1/4 to 1/3 cup batter into a circle and quickly use the bottom of the measuring cup to lightly spread the batter into a large thin circle.
Cook until the bottom is turning golden and the top of the pancake is mostly dry (with no runny wet batter spots). Use a thin spatula to flip. Cook until the second side is lightly browned.
Skillet Cooking: place a 10-inch nonstick skillet over medium heat. Brush the bottom of the pan with butter. Pour 1/4 to 1/3 cup batter into the pan. Quickly lift the pan while rotating/swirling in a circle to spread the batter evenly over the bottom of the pan.
Cook until the edges are bubbling and the bottom has golden spots. Use a thin spatula to flip. Cook until the second side is lightly browned.
Stack the Swedish pancakes on a plate (or fold into triangles). Serve sprinkled with granulated sugar and jam (or with syrup, whipped cream, strawberries, etc.).