In large bowl, cream butter and sugars until fluffy; add egg and vanilla, beat again. In separate bowl, combine flour, baking soda, salt and milled flax seed. Add to creamed mixture and stir until just combined. Fold in chocolate chips. Drop by teaspoonful 2 inches apart onto an ungreased baking sheet.
Bake for 10-12 minutes, until edges are golden. Remove for sheet and cool.