We present a lumped-element Josephson parametric amplifier (JPA) utilizing a straightforward fabrication process involving a single electron beam lithography step followed by double-angle evaporation of aluminum and in-situ oxidation. The Josephson junctions forming the SQUID are fabricated using bridgeless shadow evaporation technique, which enables reliable fabrication of relatively large ($sim9~mathrm{mu m^2}$) junctions. Our strongly coupled flux-pumped JPA achieves 20~dB gain with 95~MHz bandwidth around 5~GHz, while the center frequency is tunable by more than 1~GHz, with the additional possibility for rapid tuning by varying the pump frequency alone. Analytical calculations based on the input-output theory reproduce our measurement results closely.
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