Preheat oven to 170 degrees C. Grease a 23x33 cm baking pan; set aside.
In a large mixing bowl, beat butter, 1 cup brown sugar, instant coffee, 1/4 teaspoon cinnamon and 1/4 teaspoon salt until light and fluffy.
Stir in flour 1/2 cup at a time, blending well after each addition. Spread evenly in prepared pan.
Bake 20 minutes. Cool in pan on rack 15 minutes.
In a large bowl, beat eggs and vanilla with remaining 1 cup brown sugar, 1/4 teaspoon cinnamon and 1/4 teaspoon salt. Stir in coconut and macadamias.
Spread evenly over cooled baked layer. Bake 40 to 50 minutes, or until golden brown and firm to the touch.
Use a knife to loosen biscuits around edges while warm. Cool completely in pan on rack. Cut into 48 squares, cutting 6 strips one way and 8 strips the other way. Store in an airtight container at room temperature for one week; freeze for longer storage.