Combine the eggs, sugar, milk and vanilla in a medium bowl. While whisking together, stream in the butter, and continue to whisk until incorporated. Whisk in the flour until no lumps remain.
Preheat your waffle cone iron and coat it with a bit of canola oil to prevent the batter from sticking. Ladle enough of the batter onto the center of the iron to make a 4-inch round. Close the lid and cook until the waffle crisp is a deep golden brown, about 2 minutes. Transfer to a wire rack to cool and crisp. Repeat with the remaining batter until you have 6 to 7 waffle crisps. Crush the cooled waffle crisps into small pieces (about the size of rolled oats) and transfer to a large bowl.
Put 1 cup of the chocolate in a heatproof bowl set over a saucepan of barely simmering water (do not let the bowl touch the water). Bring the chocolate to 110 degrees F, gently stirring the chocolate as it melts. Remove from the heat and add the remaining 1/4 cup chocolate; gently stir until the chocolate is smooth and reaches 89 to 90 degrees F.
Pour the chocolate over the crushed waffle crisps and stir to coat all of the pieces, working quickly before the chocolate cools and hardens. Spread the mixture into the cups of a silicone muffin pan, making the crispy chocolate as large or small as you like. Sprinkle the sea salt over the chocolate.
Let sit at room temperature until the chocolate is fully cooled and hardened. Unmold the crispy chocolate from the cups and enjoy!