For the cupcakes, preheat oven to 350° F. Grease or paper-line 24 muffin tin cups. Set aside.
Combine chocolate and cocoa powder in a small bowl. Carefully pour in boiling water and stir until the chocolate has melted and the ingredients are well combined. Add sour cream and Framboise and mix well. Set aside.
Combine flour, baking soda, and salt in a bowl and set aside.
In the bowl of a standing electric mixer, cream together butter and sugar until well combined.
Add the eggs to the butter mixture one at a time, beating well after each addition. Beat until well blended.
Add the flour mixture, alternating with the chocolate mixture, to the egg-butter mixture. Stir until the dry ingredients until just incorporated. Stir in raspberries and their juices. Fold in chocolate chips.
Add batter to prepared muffin cups, filling each one about half full.
Bake until the cupcakes are set and a tester inserted in the center comes out clean, about 15 minutes.
Remove from the oven and cool in the pan for 15 minutes before removing to a cooling rack.
For the buttercream, place raspberries in a mesh strainer over a bowl. Press the berries against the side with a spatula to release their juices into the bowl (you should have about 1/4 cup of juice).
In the bowl of a standing electric mixer, combine butter, 3 1/2 cups of the confectioners' sugar, the raspberry juice, and Framboise. Mix slowly with the paddle attachment to combine, and then increase speed to medium-high and beat until combined. Add additional powdered sugar or milk, as needed, to achieve a smooth, creamy consistency that will hold up on your cupcakes.
Pipe frosting atop cooled cupcakes or use a small spatula to add a generous layer of frosting to each cupcake. Garnish with cookies, if desired.