In a medium-sized mixing bowl, add your softened unsalted butter, finely diced rosemary, salt, pepper, and garlic powder. Using a spatula or a sturdy fork, thoroughly mix everything together until the ingredients are well incorporated, and the mixture appears creamy and uniform in color. This should take about 2-3 minutes of gentle mixing.

Once your rosemary butter blend is creamy, it's time to shape it. If you prefer a log form, lay a piece of plastic wrap on your countertop. Spoon the rosemary butter mixture onto the wrap and shape it into a log by rolling the wrap tightly around it. Twist the ends to secure and form a neat cylindrical shape.

Transfer your wrapped rosemary butter log to the refrigerator and let it chill for at least 1 hour. This allows the flavors to meld beautifully. If you've opted for a container, simply cover it with a lid. When you take it out, the butter should be firm but spreadable.

Your delightful rosemary butter is now ready to enhance your dishes! Slice off portions as needed and let it soften just slightly at room temperature before serving.