Cream butter or margarine with mixer. Blend in whole eggs, sugar and essence. Add flour, bicarb soda and salt. When the ingredients are thoroughly mixed, add oats and pecans. Mix on lower speed until consistent.
Drop pieces of the dough using an ice cream scoop onto an ungreased cookie tray roughly 10cm apart.
Bake 8 to 10 minutes. Eight minutes would yield crispy biscuits with a chewy, slightly doughy center. For harder, crispier biscuits, bake longer. Cool on wire rack.