The chef documentation describes the optional "cookbook" attribute that enables you to specify from where the template should be retrieved:
template "/path/to/this/file" do
source "file.erb"
cookbook "myothercookbook"
mode 0440
owner "me"
group "me"
variables({
:var1 => node[:mycurrentcookbook][:var1],
:var2 => node[:mycurrentcookbook][:var2]
})
end
This enables common templates to be re-used.