Wet Ingredients 8 tablespoons unsalted butter, divided (Note 1) 1 tablespoon white vinegar (not white wine vinegar) 1 cup + 3 tablespoons whole milk, at room temp 1 teaspoon pure vanilla extract 1 large egg, at room temp Dry Ingredients 1 and 1/4 cups white all-purpose flour 2 tablespoons white granulated sugar 1/2 teaspoon fine…