In a bowl, soak dates in hot water for about 10 minutes. This softens them and makes them easier to purée.
After soaking, drain the dates and place them in a blender or food processor. Add a splash of milk and blend until smooth. You want a thick, creamy consistency that will incorporate seamlessly into the sauce.
In a medium saucepan, melt the butter over medium heat until it is fully melted.
Stir in the puréed dates and mix well, allowing the flavors to meld together for a minute.
Gradually pour in the remaining milk while stirring, adjusting the amount to achieve your desired consistency (thicker for drizzling, thinner for dipping).
Add the kosher salt, vanilla, and optional baking soda. Stir well to combine. The baking soda helps create a lighter texture, but it’s completely optional.
Allow the sauce to simmer gently for 5-10 minutes, stirring occasionally. This will help deepen the flavors and thicken the sauce slightly.
Remove from heat and let the sauce cool slightly before serving. It can be drizzled warm over your favorite desserts or stored in an airtight container in the refrigerator for up to two weeks.