Mix the flour, oats, baking soda, salt, and cinnamon together in a bowl.
In another bowl, mix melted butter, brown and confectioner’s sugar together. Add the egg and vanilla extract. Then add the instant coffee and mix the flour and sugar mixtures together.
Add the chopped nuts, if you desire. Bake at 180°C/350°F for approx. 10 min., then wait for another 2 min. before moving cookies to the cooling rack.