The chef feat grants, among other benefits, the ability to cook a meal during a short rest
As part of a short rest, you can cook special food, provided you have ingredients and cook's utensils on hand. You can prepare enough of this food for a number of creatures equal to 4 + your proficiency bonus. At the end of the short rest, any creature who eats the food and spends one or more Hit Dice to regain hit points regains an extra 1d8 hit points. 
Cook's utensils themselves already grant a bonus when used to cook a meal during a short rest
As part of a short rest, you can prepare a tasty meal that helps your companions regain their strength. You and up to five creatures of your choice regain 1 extra hit point per Hit Die spent during a short rest, provided you have access to your cook’s utensils and sufficient food. 
Do these benefits stack so that you can give in total 1d8+
number of Hit Dice spent to yourself and up to five creatures who use hit dice?
 Tasha's Cauldron of Everything, page 79
 Xanathar's Guide to Everything, page 81