Melt butter in a large pot and add in the garlic and red pepper flakes. Do this on a medium heat while stirring regularly to not burn the garlic. Cook for about 2 minutes, until you really smell the garlic.
Add in the champagne, and clams. Cover the pot with the lid and let cook for 5-6 minutes. You might hear popping noises as the clams open up.
Remove the lid and give you clams a good stir. All the shells should be wide open. If they’re not fully open, cover again and cook for another minute or two. If you have any clams that didn’t open at all, remove it and throw it away.
Once all the clams are wide open, squeeze fresh lemon juice over top. Add the fresh parsley. Give everything a cook stir, and serve right away.