In a medium saucepan with the heat off, whisk together cocoa powder, sugar, cornstarch, and salt. Gradually stir in RISE Chocolate Oat Milk until smooth.
Turn the heat on to medium and bring to a simmer, frequently stirring.
Once it starts to bubble on the edges reduce heat to low and continue to stir until thickened, about 2 minutes.
Remove from heat and stir in chocolate chips and vanilla.
Transfer to a glass container and press plastic wrap on the surface to prevent a film from forming.
Transfer to the fridge and let cool for at least 2 hours.
To serve, spoon into cups and top with your favorite toppings.