We report the first example of a chemical reaction in a new type of surfactant aggregates called "spherulites" or "onions". Spherulites are spherical microdomains (200-1000 nm)of lamellar phase. They are prepared by means of shear of a lamellar phase under controlled conditions. Spherulites can be considered as surfactant vesicles with a dense multilamellar structure. Chemical reduction of copper(II) ions encapsulated into spherulites by hydrazine demonstrates the possibility of using this new surfactant assembly as chemical microreactors. We describe the process of encapsulation of copper(II) ions into spherulites. The use of a ligand-like surfactant proved to be efficient in preventing the leakage of these ions despite spherulite permeability to small hydrosoluble molecules. Encapsulation ratios up to 80% are obtained. When hydrazine is added to an aqueous suspension of Cu(II)-containing spherulites, hydrazine diffuses into the spherulites and chemical reduction of the entrapped ions occurs. The formation of small Cu2O particles (10-30 nm) is observed throughout the multilayered structure of the spherulites. The suspension of nanoparticles embedded in the surfactant structure is stable, and the nanoparticles can be recovered by destruction of the spherulites.