In a small or medium saucepan, whisk together sifted cocoa powder, sugar, and water over medium heat. Bring to a simmer, then lower the heat. Stir frequently as it simmers for about 3 minutes; it shouldn’t come to a rolling boil. The syrup will bubble and expand, becoming slightly thicker.
Remove from heat and stir in vanilla extract and salt. Allow to cool, and transfer to a glass jar or bottle. Chill in the fridge before using for optimal flavor and texture, it thickens up quite a bit in the fridge and the flavor really comes together!
Store in an airtight container in the fridge for up to 1 month. Use it to make chocolate milk, hot cocoa, mochas, drizzle on desserts, ice cream, and more!