A method of manufacturing a component having first and second layers, the first and/or second layers including one or more depressions provided on a surface of the respective layer. The method including: arranging the first and second layers so that they face one another and with the depressions on inner facing surfaces of the layers； diffusion bonding the first and second layers together about their edges； applying a first differential pressure across each of the first and second layers to evacuate an inner space defined by the layers, thereby forming one or more depressions on an outer facing surface of the first or second layer； and applying a second differential pressure across each of the first and second layers to expand the inner space defined by the layers.
