Preheat oven to 350 degrees and line muffin pans with cupcake liners.
Sift cake mix into a large bowl. In another bowl, combine the eggs, milk, oil, vanilla yogurt, and vanilla extract together until smooth and creamy. Stir mixture into the cake mix until combined.
Fill cupcake liners 3/4 full and bake for 17-22 minutes or until a tester inserted into the center comes out clean. Remove from the oven and let cool for a few minutes before moving the cupcakes to a cooling rack to cool completely.
Make the chocolate buttercream frosting. Beat the butter for 2 minutes with a beater. Add cocoa powder, milk, gelatin, vanilla extract, and milk and beat until smooth. Slowly add powdered sugar until you reach your desired consistency.
Once cupcakes have cooled completely, use a knife to cut out a hole into each cupcake. Spoon some raspberry filling into each hole in the cupcakes.
Spread the chocolate buttercream frosting over filling and top with mini marshmallow bits and sprinkles. Enjoy!