1. In a medium nonstick pan over medium heat, melt the butter. Once the butter is melted, continue cooking until the butter is golden brown. Remove from the heat and set aside. The residual heat will make the butter a little more brown, so err on the side of golden brown versus dark before you turn off the heat.
2. In a medium bowl, gently whisk together the eggs, egg yolk, water, milk, and salt until just combined. Add the flour and whisk until smooth. Slowly pour the browned butter into the mixture, whisking constantly. If necessary, strain the mixture to remove any lumps.
3. Use a paper towel to wipe out the same nonstick pan used to melt the butter. Set the pan over medium heat. Using a 1/3-cup measure, scoop the batter and pour it into the center of the hot pan. Using a rotating motion with your wrist, swirl the batter around and out to the edges of the pan- the thinner, the better. Return the pan to the heat and cook for 2 minutes. Use a rubber spatula to lift up the edge of the crepe and flip the crepe over. Cook on the other side for 30 seconds to 1 minute, depending on how golden you like it.
4. Slide the crepe onto a plate and spread with 1 tablespoon of the Nutella (or as much as you like). Fold the crepe in half, then fold in half again to form a triangle. You can also just roll up the crepe loosely like a carpet. Garnish with desired toppings.