Pour the almond milk, coconut milk, maple syrup, arrowroot starch, and vanilla into a medium-sized pot. Heat on the stove over high heat, whisking generously to mix in the arrowroot starch. Continue to whisk until the mixture begins to bubble. Then, turn the heat down to medium-heat and allow the mixture to simmer for another 20 minutes. Stir every now and then to prevent burning. The mixture will begin to thick up slightly. Be sure to scrape the bottom of the pan and the sides when stirring.
1 ½ cup almond milk, 1 13- oz can full-fat coconut milk, ½ cup pure maple syrup, 3 tablespoon arrowroot starch, 1 teaspoon vanilla extract