Compound butter is simply butter enhanced with supplementary flavors. Herbs, spices, other aromatics and even cheeses are stirred or whipped into room temperature butter, which is often then chilled back down to be used later to top meat, vegetables or enhance a sauce.
Blue Cheese Butter Recipe
1 cup unsalted butter
1/2 cup blue cheese
1/4 cup parsley, minced
2 tbsp shallots, minced
1 tbsp fresh grated horseradish
Salt & pepper, to taste
Bring the butter to room temperature. Fold the remaining ingredients into the butter, and mix well to distribute evenly.
Place the butter on a piece of plastic wrap. Fold the plastic over the butter and form the butter into a tube/log shape. Refrigerate until set.
Slice pats of butter and melt over hot steak as soon as it comes off the grill.