For the Chocolate Cupcakes: Preheat the oven to 350°F (180°C) and line a 12-cup cupcake tin with cupcake liners. In a medium bowl, whisk together the flour, cocoa powder, baking powder, baking soda, and salt. In a separate large mixing bowl with a hand mixer, beat the sugar, egg, milk, oil, and vanilla until smooth. Add the dry ingredients and mix just until combined. Pour in the hot water and mix until the batter is smooth and thin. Divide the batter between the cupcake liners, filling each about two-thirds full. Bake for 16–18 minutes or until a toothpick inserted into the center comes out clean. Allow cupcakes to cool completely.
For the Ganache: Place the chocolate chips in a heat-safe bowl. Warm the cream until steaming and pour it over the chocolate. Let it sit for 2 minutes, then stir until smooth and glossy. Chill for about 15 minutes until slightly thickened but still spoonable.
Fill the Cupcakes: Use a cupcake corer or a small knife to remove a small center from each cooled cupcake. Spoon or pipe the ganache into the center of each one. Replace the top piece if desired.
For the Strawberry Buttercream: Add the freeze dried strawberries to a food processor and pulse until a fine powder forms. Beat the softened butter and vanilla in a large mixing bowl with a hand mixer until light and creamy. Add the powdered sugar gradually until completely combined. And the freeze-dried strawberry powder and mix on low until combined. If the buttercream becomes too thick after adding the strawberry, you can add 1 tablespoon of cream until you reach the desired consistency. Beat on medium-high until fluffy.
Decorate: Pipe the strawberry buttercream onto the cupcakes using a piping bag with a large star tip. Warm the remaining ganache slightly if needed, then drizzle it over the frosting. Top each cupcake with a fresh strawberry slice.