Step 1 – Preheat oven to 180°C/160°C fan-forced. Grease and line a 3cm-deep, 19cm x 29cm (base) slice pan with baking paper, allowing a 2cm overhang at long ends.
Step 2 – Combine flour, oats, sugar and coconut in a large bowl. Make a well in the centre.
Step 3 – Place butter and syrup in a saucepan over low heat. Cook, stirring occasionally, for 8 to 10 minutes or until smooth. Combine bicarbonate of soda and boiling water in a jug. Remove butter mixture from heat. Stir in bicarbonate of soda mixture. Add to flour mixture. Stir to combine.
Step 4 – Transfer to prepared pan. Using the back of a spoon, press mixture evenly into pan. Bake for 25 to 30 minutes or until golden. Cool in pan. Cut into squares. Serve.