Abstract: I will present a simple holographic model of closed universes originating from the black hole interior in JT gravity. The model relies on the insertion of a heavy operator to support the baby universe, together with a first-order phase transition between a black hole phase and an empty AdS phase. To this end, I will employ the Maldacena–Qi phase transition of two coupled SYK systems to construct thermal pure states in SYK dominated by the baby universe saddle below the transition temperature. The bulk entanglement with the universe remains parametrically large in N below the transition. I will conclude by discussing various properties of this model.