Bring 6 cups of water to a boil. Add sugar and pasta and cook for approximately 9 minutes. Remove and drain.
Melt white chocolate chips with butter, half and half, and vanilla extract in a double boiler over medium heat. Whisk until chocolate is completely melted. Stir in white chocolate liqueur. Turn off heat and allow sauce to keep warm in double boiler.
Place a portion of chocolate pasta on a plate. Top with raspberries and drizzle with chocolate sauce. Serve warm.