Preheat oven to 425 degrees F.
Grease and flour 2 to 4 ramekins (depending on the size of your ramekins). Reserve.
In a large bowl, whisk together the egg, egg yolks and vanilla extract until creamy and pale.
Add the dulce de leche and salt and continue whisking until smooth. Then, add the flour and gently whisk or fold with a wooden spoon, being very careful not to overmix.
Pour the batter into the prepared ramekins, leaving a little space on top for the cakes to grow.
Bake the cakes in the preheated oven for about 15 minutes or until the edges are set but the center is still jiggly. Remove from oven and let the dulce de leche cakes cool for about 1 minute.
Run a sharp knife around the cakes and flip them into individual plates.
Garnish with powdered sugar and fresh berries, if desired, and serve.