Preheat the oven to 450 F.
Butter small ramekins. In a medium saucepan, combine the butter and the chocolate over medium heat. Heat, stirring occasionally to combine, until the chocolate and butter are melted.
In a medium bowl, whisk together the yolks and eggs, then add the sugar. Add the chocolate mixture and whisk until well combined.
Then whisk in the all purpose flour. Spoon two-thirds of the batter into the prepared ramekins, then add 1 tablespoon of dulce de leche on top. Cover with the remaining chocolate batter.
Place the ramekins on a baking sheet and bake for about 10 minutes. The outside of the cake will be ready, but the inside should be very soft.