A casting core for an airfoil according to an example of the present disclosure includes, among other things, a first portion extending in a first direction and corresponding to a first cavity of an airfoil. The first portion defines a reference plane along a parting line formed by a casting die. The first portion defines a plurality of grooves corresponding to a plurality of trip strips of the airfoil. Each of the plurality of grooves defines a respective groove axis, and the plurality of grooves are distributed in the first direction along a first side of the reference plane such that one or more of the groove axes are oriented with respect to a pull direction of the casting die. A method for fabricating a gas turbine engine component is also disclosed.