Out of heavy cream? For 1 cup, whisk 3/4 cup milk with 1/4 cup melted butter. Works in sauces, soups and baking, but it will not whip.
1 cup heavy cream = 3/4 cup milk + 1/4 cup melted butter (cooking and baking only)
Good for sauces, soups and baking. It won’t whip, so it is not a swap for whipped cream.