In a large bowl, whisk together the egg yolks, the vanilla, the salt, the pumpkin purée, the sugar (1/3 cup granulated) and the brown sugar until it’s smooth and well blended. Then, slowly pour it into the cream mixture, stirring until well blended. Strain it in a sieve. Divide the mixture among the molds and place them in a large baking pan. Add the boiling water to fill the pan halfway up the sides of the molds. Cover the pan loosely with aluminum foil and bake, for about 30 minutes.