Heat the oven to 350°F. Line a cupcake pan with paper liners.
Combine the flour, sugar, cocoa powder, baking powder, baking soda, and salt in a large bowl and whisk together.
Combine the egg, buttermilk, oil, and vanilla extract in a separate bowl and whisk together.
Add the wet ingredients to the dry ingredients in the bowl of a stand mixer and mix until fully combined.
Add the hot water to the batter and mix again, scraping the sides of the bowl as necessary, until combined. The batter will be thin.
Fill cupcake liners only ½ full, then bake the cupcakes for 18-21 minutes. The tops will bounce back when you touch them with a finger, or a toothpick will come out with only a few moist crumbs when they're done.
Cool completely before frosting.
To make the frosting, beat the softened butter in a large mixing bowl until creamy and light, about 2 minutes. Add powdered sugar and freeze-dried strawberry powder. Mix on low speed until they start to combine. Add vanilla extract and heavy cream. Gradually increase the mixer speed and beat for 3-5 minutes until light and spreadable.
Transfer the frosting to a piping bag fitted with a decorative tip. Pipe swirls of frosting on top of the cooled cupcakes.
Melt the chocolate melting wafers according to the package instructions. Dip the strawberries in the melted chocolate, then transfer the chocolate-covered strawberries to a baking sheet lined with parchment paper to set up.
Once set, decorate each cupcake with a chocolate-covered strawberry.