In a mixing bowl, whisk together milk and eggs until well combined and frothy. Gradually sift in flour, whisking continuously to avoid lumps. Let the batter rest for 10 minutes.

Heat a non-stick skillet over medium heat and lightly coat it with butter or oil. When hot, ladle batter into the skillet, swirling to cover evenly.

Cook the crepe for about 1-2 minutes until the edges lift and turn golden brown. Flip and cook for another minute until lightly golden and cooked through.

Sauté spinach in the skillet until wilted, about 3 minutes. Scramble eggs in a bowl, add to the skillet, and mix in cheddar cheese until melted.

Lay a warm crepe flat, add a scoop of filling in the center, fold or roll, and serve while warm.