Warm the oat milk on the stove over medium-low heat until hot but not boiling. Simmer for 5 minutes.
Combine cocoa powder, honey, and salt with 2 tablespoons of warm oat milk to make a hot chocolate slurry. Mix until there are no lumps in your cocoa powder.
Add the hot cocoa slurry to the warm oat milk, and mix well.
Simmer on low for 3-5 minutes more until your hot chocolate is slightly thickened and creamy.
Stir in the vanilla extract
Pour into two hot cocoa mugs and serve with toppings of your choice.