Milk Chocolate Sauce

Place 4 oz. milk chocolate, finely chopped and ½ tsp. Diamond Crystal or ¼ tsp. Morton kosher salt in a medium heatproof bowl. Heat ¾ cup heavy cream in a small saucepan just until steaming (do not let it come to a boil) and pour over chocolate. Let sit until chocolate is melted, about 5 minutes. Add 2 Tbsp. unsalted butter, room temperature, and whisk until butter is melted and incorporated and mixture is smooth. Serve warm. Do Ahead: Chocolate sauce can be made 5 days ahead; chill covered. Rewarm over low heat, stirring, or in a microwave at medium power in 30-second bursts until just warm.