  We present differential cross sections for the production of top-quark pairs
in conjunction with up to two jets, computed at next-to leading order in
perturbative QCD and consistently merged with a parton shower in the
Sherpa+OpenLoops framework. Top quark decays including spin correlation effects
are taken into account at leading order accuracy. The calculation yields a
unified description of top-pair plus multi-jet production, and detailed results
are presented for various key observables at the Large Hadron Collider. A large
improvement with respect to the multi-jet merging approach at leading order is
found for the total transverse energy spectrum, which plays a prominent role in
searches for physics beyond the Standard Model.
