Scrape vanilla bean seeds into a small saucepan over medium heat; add butter and cook until melted, 2 to 3 minutes. Whisk vanilla butter, brown sugar, egg whites, vanilla extract, and salt together in a bowl; add flour and beat until batter is smooth.
Preheat a waffle cone maker according to manufacturer's instructions.
Pour batter into the preheated waffle maker and cook according to instructions.
Immediately wrap around a cone-shaped dowel or press into a bowl-shaped mold. Let each cone or bowl cool for a few minutes. Store in an airtight container for up to 2 days.