A thermosetting protective and/or decorative coating composition that includes a co-reactable solid, particulate mixture of a film-forming material that includes a copolymer containing functional groups and a crosslinking agent having at least two functional groups that are reactive with the functional groups in the copolymer. The film-forming material makes up from 20 to 95 wt. % and the crosslinking agent makes up from 5 to 80 wt. % of the composition. The composition is applied as a coating and cured, forming a bicontinuous morphology where the film-forming material and the crosslinking agent form separate phases resulting in a low gloss coating as indicated by a specular gloss measurement of not more than 10 gloss units measured at 60.degree. with an appropriate instrument. A method of coating a substrate using the composition, substrates coated using the method, and a multi-component composite coating composition that includes the composition are disclosed.