Preheat oven to 325 degrees Fahrenheit.

Beat egg whites until soft peaks form.

Add sugar, salt, cinnamon, and vanilla extract to the egg whites.

Continue beating until stiff peaks form and the mixture turns glossy.

Gently fold in pecan or walnut halves until they are well coated with the egg white mixture.

Melt butter in a 9x13-inch baking pan by placing it in the preheated oven.

Evenly spread the coated nuts over the melted butter in the pan.

Bake for 30 minutes, stirring and turning the nuts every 8 minutes to prevent burning and ensure even cooking.

Continue to bake and turn nuts until no butter remains in the pan.

Carefully remove the hot nuts from the oven and place them on foil to cool.

Allow the nuts to cool completely.

Store the cooled nuts in an airtight container for several weeks.