We investigate Landau level formation in closely coupled double quantum wells by measuring the longitudinal resistance (R xx ) as a function of both perpendicular (B ⊥ ) and in-plane (B ‖ ) magnetic fields. B ‖ distorts the dispersion curve resulting in a continuously tunable, non-parabolic, two-component system. B ⊥ causes Landau level formation in each branch of the dispersion. These two ladders of Landau levels have multiple crossings because the cyclotron masses and Fermi energies of the two components change in opposite directions with B ‖ . Due to magnetic breakdown of the Fermi surface, a third set of Landau levels, independent of B ‖ , occurs at slightly higher B ⊥ (≈1T).