Preheat the oven to 180C/350F and line a muffin tin with paper cases.
Sift the flour, sugar, salt, baking powder and cocoa powder into a large mixing bowl.
In a separate jug, whisk together the milk, oil, vanilla and egg. Pour into the dry ingredients and whisk until combined.
Divide evenly between the paper cases, and bake for 17-20 minutes, or until dry and springing back when pressed. Place on a wire rack to cool completely.
To make the buttercream, dissolve the malt powder in the hot water in a small bowl and set aside.
Place the egg whites and sugar into a heat proof bowl, over but not touching a saucepan filled with simmering water (aka a bain marie). Whisk gently (not to incorporate any air), until the mixture reaches 65c/145F - or until the mixture feels hot to the touch, when you rub some between your fingers, you can feel no grains of sugar.
Transfer the mixture to the bowl of a stand mixer, fitted with the whisk attachment, and beat on a medium-high speed, until the mixture is tripled in volume and completely cool. It should look like meringue.
When the mixture is completely cool, begin beating on the butter adding it a tablespoon at a time, with the mixer running still at a medium-high speed.
When all the butter is incorporated, whisk through the vanilla and the dissolved malt powder.
Top the cooled cupcakes with a generous slathering of buttercream, a drizzle of caramel, and a scattering of crushed malt balls.
Recipe by The Sugar Hit at http://www.thesugarhit.com/2016/03/salty-dawgs-salted-chocolate-malted-cupcakes.html