Add the evaporated milk, heavy cream or whipping cream, vanilla extract and the keto sweetener you prefer (xylitol or allulose) to the pan, and place it over medium-high heat to bring it to a boil. Stir as the mixture gently boils, or vigorously simmers. It will slowly thicken, and reach the condensed milk stage before turning into dulce de leche.
Dulce de leche is simply sweetened condensed milk that has been further cooked. A popular way of making dulce de leche is putting a sealed can of condensed milk inside a pressure cooker or instant pot and cooking it until it turns into dulce de leche. This was, by the way, my favorite!
Keep stirring as the dulce de leche bubbles and thickens over a medium heat. It will need a further 5-10 mins of cooking. It will turn a darker shade of brown and take on a slight orange-red hue as it darkens. It should be thick enough to leave a clear channel in the pan when a spoon is run through and then add a pinch of salt.
This dulce de leche was my husband’s favorite one in terms of flavor. Place rack in the pressure cooker, and then the can of sweetened condensed milk, laid on its side on top of the rack. Pour in enough water to cover can by 1-2 inches above. Secure lid, turn on the pressure cooker and seal valve.