In an embodiment, the first component carrier has a cavity, and the second component carrier is inserted at least partially into the cavity. Correspondingly, the method may comprise forming a cavity in the first component carrier and at least partially inserting the second component carrier into the cavity. In the context of the present application, the term “cavity” may particularly denote a recess in a layer structure or in a plurality of stacked layer structures, for instance a recess in a (for example fully cured) core. For example, such a cavity may be a through hole or a blind hole. For instance, the cavity may be formed by laser drilling or mechanically drilling. It is however also possible to form a cavity by embedding a release layer in the first component carrier. Such a release layer poorly adheres to surrounding component carrier material and thereby defines a target delamination position upon separating material above such a release layer, for instance by laser cutting or mechanical cutting. A piece above the release layer may then be taken out from the first component carrier, so that the cavity is obtained. Placing the second component carrier in a cavity of the first component carrier will automatically result in a reliable mechanical protection of the sensitive second component carrier in an interior of the first component carrier. Moreover, inserting the second component carrier in a cavity of the first component carrier may allow placing the second component carrier spatially directly next to an embedded component which may therefore be contacted by the electrically conductive traces of the second component carrier in a highly efficient way and with short signal paths.