How to Make It
Put the eggs, milk, flour, melted butter, sugar and salt in a blender and blend for 30 seconds or until smooth. Scrape down the mixture from the sides of the blender and repeat if necessary. Cover and chill for at least 1 hour (2 hours is preferable) and up to 24 hours.
If the chilled batter has separated, gently stir it until it comes back together. Lightly butter a 6- or 7-inch nonstick pan and heat over medium-high heat until hot.
Lift the pan from the heat and pour in 2 to 3 tablespoons of batter, tilting and rotating the pan to coat the surface. Return the pan to the heat and cook the panqueque until almost dry on top and lightly browned on the edges, about 1 minute. Loosen the edges with a spatula and, using your fingers or a spatula, flip over the panqueque and cook the other side for about 15 seconds, or until lightly browned. Make more panqueques with the remaining batter in the same manner, wiping the pan with butter (we peel back the paper on the stick of butter and wipe it on the pan), as needed, and stacking the panqueques after they are cooked.
Spread the top of each panqueque with about 2 teaspoons of dulce de leche and fold or shape as desired.