Cut fillet into thin strips. Heat 2 tablespoons of the oil in medium pan; cook fillet strips, in batches, until browned then remove from pan and keep warm. Heat remaining oil in same pan, add onions and garlic; cook, stirring, until onions are soft. Add paprika and mushrooms; cook, stirring, 2 minutes. Return beef to pan with paste, wine, juice, cream, milk; add chives; stir, without boiling, until heated through.