Astrophysical jets associated with supermassive black holes (BHs) are believed to derive their power from the rotational energy of the BH itself, akin to how the Crab Nebula is powered by its pulsar. The Blandford-Znajek (BZ) mechanism, an electromagnetic Penrose process, provides a framework for understanding the physics of jet energetics. Specifically, it predicts the jet efficiency—the ratio of outflowing jet power to inflowing accretion power—to scale quadratically with the magnetic flux at and angular velocity of the black hole horizon. For rapidly spinning Kerr BHs, numerical simulations reveal jet efficiencies exceeding unity, a clear indicator of energy extraction from the black hole. At moderate spins, confirmation of energy extraction relies on the alignment of measured jet efficiencies with the BZ prediction. Over the past decade, this prediction has been validated across Kerr BHs with varying spin values. We present new findings from a large suite of magnetohydrodynamics accretion simulations conducted in spinning non-Kerr spacetimes, demonstrating that the BZ mechanism operates universally, extending its applicability to arbitrary BHs.