Add the butter to a medium saucepan or skillet and place it over low heat. Gently warm the butter just till it melts, NOT bubbling or sizzling. Keeping the temperature low prevents the acids you’ll add later from breaking the emulsion.
Once the butter is melted, remove the pan from the heat and let it cool slightly. This is key — the butter should stay warm but not hot before adding the lemon juice.
Add the remaining ingredients for the butter and whisk until it’s well combined and smooth.
Taste, and adjust seasoning. If you want a little more smoke or heat, you can bump the chipotle powder by another half teaspoon.
Serve it your way: For dipping sauce: Serve warm in a small cast-iron skillet or ramekin right away.For compound butter: Let it cool to room temperature, then transfer to a small bowl or roll it in parchment paper and refrigerate until spreadable.