The composition of the protein corona covering any nanoparticle (NP) when it enters a biological fluid determines the parameters of the NP’s interaction with the body. To “control” these parameters, it is important to know the composition of the protein corona, the determination of which is a complex task associated with the two-layer organization of the corona (hard and soft coronas). In a previous publication, we reported obtaining lipid-coated NPs with a full protein corona, isolating them, and proving the presence of the corona on the surface of the NPs. This work reports on the preparation, isolation, and purification of lipid-coated NPs bearing a hard corona. The protein corona composition was determined by using the LC–MS/MS method. Thirty-seven serum proteins were identified with a high degree of reliability. The hard corona contained various apolipoproteins, including apolipoprotein E, which can potentially affect the penetration of NPs into the cell.