Software engineering methods describe structured, repeatable best practice approaches for the engineering of software systems. The project team of a software project enacts a method and applies the described activities. As methods are superior to ad-hoc build and fix approaches, they benefit the creation of high-quality software. However, for the efficient use of methods, first, they need to be based on state of the practice method content, second, they need to be tailored to the project context, and third, they need to be enacted as prescribed. Otherwise, outdated, unsuitable, or wrongly enacted methods can impede the creation of the software system. While other approaches focus on supporting some of these aspects, our approach is a holistic tool-supported approach that covers all of them. It allows creating formally defined composition-based method models. First, method models are composed from formal building blocks that represent method content and are stored in an extensible, updatable repository. Second, they are composed specifically for a project and tailored to its characteristics. Here the novel notion of method patterns is used to guide the composition process. Third, their correct enactment is supported with a process engine. Our proof-of-concept implementation demonstrates the feasibility of the approach. It provides tooling to define building blocks, to compose them to method models consistently, and to execute them with standard process engines.