Preheat oven to 375 degrees Fahrenheit.

In a large bowl, beat together the softened butter, shortening, brown sugar, and sugar until fluffy.

Add the vanilla, baking soda, and salt, mixing well after each addition.

Beat in the egg until well incorporated.

Gradually add the flour, about 1/2 cup at a time, mixing until just combined.

Stir in the chocolate chips.

Roll dough into balls approximately 1 1/2 to 2 inches in diameter.

Place the dough balls 2 to 3 inches apart on an ungreased cookie sheet.

Bake for 8 to 10 minutes, or until slightly browned.

Let cool on the cookie sheet for about 2 minutes before transferring to a wire rack or paper towels to cool completely.

Store in an airtight container.