In a small bowl, combine the butter, lemon juice, zest and the chili paste or sriracha sauce. Using a wooden spoon, press and mix everything together. Lay a 10x10-inch piece of plastic wrap on a flat surface. Dollop the butter on the plastic wrap in a log shape. Roll the butter in the plastic wrap, creating a log. Put in the fridge for a few hours or until you're ready to use.