In a medium bowl, add the softened butter, parsley, Cajun seasoning, brown sugar, chili powder, garlic powder, dried thyme, and cayenne pepper.
Using a fork or a hand mixer, thoroughly combine all the ingredients until they are evenly mixed. If you prefer a hint of acidity, add lemon juice and mix well. Spread a little on a saltine cracker, taste, and adjust the flavors as desired.
Transfer the mixture into a serving bowl. Alternatively you can place the mixture onto a piece of plastic wrap or parchment paper, roll it into a log shape, and twisting the ends to seal it tightly.
Refrigerate for at least 1 hour, or until it is firm. You can also freeze it for longer storage.
Use it to top grilled meats, seafood, vegetables, or spread it on bread.