1 1/2 sticks (6 ounces) unsalted butter, cut into tablespoons and chilled
Freshly ground pepper
In a medium saucepan, heat the olive oil. Add the garlic and cook over moderately low heat, stirring constantly, until golden, 3 to 5 minutes. Transfer to a blender, add the soy sauce and puree.
Return the garlic-soy mixture to the pan and bring to a boil. Reduce the heat to low. Remove the pan from the heat and whisk in the chilled butter, 1 tablespoon at a time, until it is incorporated and the sauce is smooth. Return the pan to the heat now and then to keep the sauce hot enough to melt the butter but do not let it boil. Season generously with pepper.
The sauce, without the butter, can be refrigerated for up to 2 days. Bring to a boil and proceed.
Steaks, fish, chicken breasts, shrimp, steamed spinach or broccoli.