In this contribution, an overview of the progress in the design of an enhanced FLOX® burner is given. A fuel flexible burner concept was developed to fulfill the requirements of modern gas turbines: high specific power density, high turbine inlet temperature, and low NOx emissions. The basis for the research work is numerical simulation. With the focus on pollutant emissions a detailed chemical kinetic mechanism is used in the calculations. A novel mixing control concept, called HiPerMix®, and its application in the FLOX® burner is presented. In view of the desired operational conditions in a gas turbine combustor this enhanced FLOX® burner was manufactured and experimentally investigated at the DLR test facility. In the present work experimental and computational results are presented for natural gas and natural gas + hydrogen combustion at gas turbine relevant conditions and high adiabatic flame temperatures (up to Tad = 2000 K). The respective power densities are PA = 13.3 MW/m2/bar (NG) and PA = 14.8 MW/m2/bar (NG + H2) satisfying the demands of a gas turbine combustor. It is demonstrated that the combustion is complete and stable and that the pollutant emissions are very low.