Chop the milk chocolate into chunks and heat them with the coconut oil in a saucepan on medium heat until melted. Take the chocolate mixture off of the heat and let it cool.
Use a hand mixer to beat the eggs and powdered sugar for about 5 minutes until the mixture becomes smooth and creamy. Add the cocoa powder, milk, vanilla extract, and pinch of salt and continue to mix on low speed until a smooth batter forms.
Gradually add the warm chocolate and coconut oil mixture, and continue to blend until combined.
Crush the graham crackers by hand, then fold them into the chocolate mixture.
Place a small glass bowl facedown in the bottom of a much larger glass bowl. Pour the cake batter into the bowl, making sure the small bowl stays in place at the bottom. Transfer the large bowl to the refrigerator and chill overnight.
Once the cake has chilled, remove the bowl from the refrigerator and place a large plate over the top of it. Flip the bowl over so that the cake is sitting upright on the plate and use a hair dryer to heat the volcano cake enough so that it drops out of the large bowl. Repeat this technique to remove the small bowl from the top.
Blow up a clean balloon so that it fits snugly into the well at the top of the chilled volcano cake. Temper the white chocolate and pour it over the balloon, leaving the very top section uncovered, and let the white chocolate set. Once the white chocolate has hardened, pop the balloon and remove it from the volcano.
To make the raspberry lava sauce, bring the sugar and water to a boil. Continue to heat the mixture slowly until it becomes thick and takes on a caramel-like consistency and color. Stir in the thawed raspberries, vanilla extract, and orange juice, return to a boil, and let the mixture continue to simmer until the raspberries begin to break down. Mix the corn starch with some water and pour the mixture into the simmering raspberry sauce to thicken it. Once the hot raspberry lava sauce is ready, pour it directly into the hollowed-out white chocolate well on top of the volcano.
