The Topology and Orchestration Specification for Cloud Applications (TOSCA) enables the description, provisioning, and management of complex cloud applications in a portable way. TOSCA, therefore, provides a comprehensive yet complex set of mechanisms that may hinder users from unleashing its power due to misusing or neglecting parts of those mechanisms. TOSCA has just been standardized and, although it seems to be highly adopted in industry, there is a lack of systematic research of its features and capabilities. In this work we discuss the design of basic building blocks for cloud applications, called node types, and show how they can benefit from a deep integration with TOSCA. We developed a generic architecture for the realization of TOSCA node types, show an implementation of this architecture and validate it based on a sample cloud application. Our work gives an insight into the capabilities of TOSCA with respect to enable the creation of portable cloud services based on a set of composable building blocks.