Despite many years of scientific work on evolving ultra-short laser pulses with high energy, there is still a need for even shorter pulses with higher peak intensity for science, industry, and defence. The most popular method for amplification - chirped-pulse amplification (CPA) is limited by gain-narrowing and can be worked around by nonlinear pulse compression. This does however increase the complexity of the setup. The newest regime for amplification reported by the group of F. Wise can deliver short pulses close to the transform limit and is a simple, undemanding setup [1] , [2] . Gain-managed nonlinear (GMN) amplification regime is based on the interplay between nonlinear spectral broadening and a longitudinally varying gain profile. The numerical simulations performed alongside the experiment confirm the existence of the GMN amplification regime. Here, we demonstrate a simple single-stage amplifier that can deliver pulses shorter than 55 fs with energy up to 24 nJ, which corresponds to 3 W of average power and 451 kW of peak power.