Step 1: In a heavy-bottomed saucepan, combine the granulated sugar and water. Stir gently to moisten all the sugar.
Step 2: Cook over medium heat without stirring. Allow the sugar to dissolve and then boil. You can swirl the pan occasionally to ensure even cooking.
Step 3: Continue to cook until the sugar syrup turns a rich amber color. This usually takes about 8-12 minutes. Do not let it burn!
Step 4: Once the desired color is reached, immediately and very carefully pour the warmed heavy cream into the sugar mixture. Be cautious as it will bubble up vigorously. Whisk continuously until smooth.
Step 5: Remove the pan from the heat. Add the cubed butter, miso paste, and vanilla extract. Whisk until the butter is fully melted and the miso paste is thoroughly incorporated, creating a smooth, glossy sauce.
Step 6: Taste and add an additional pinch of sea salt if desired, though the miso usually provides enough salinity.
Step 7: Pour the Miso Caramel Sauce into a heatproof jar. It will be quite thin initially, but will thicken considerably as it cools.
Step 8: Allow to cool completely at room temperature before using or storing. Store in an airtight container in the refrigerator for up to 2 weeks. Reheat gently in a microwave or on the stovetop with a splash of water or milk to restore its pourable consistency.