A high mass-flow sensing apparatus and method of forming the same, comprising a flow tube bypassed in a flow path defined by a flow channel, through which a fluid flows. A flow sensor can be disposed in the flow tube for measuring a flow rate of the fluid in the flow channel. A set of narrow rectangular flow restrictors can be molded into the flow tube and adjacent to the flow sensor. Each flow restrictor can include several rectangular cutouts that are molded into upstream and/or downstream portions of the flow tube in order to limit the flow rate of the fluid across the flow sensor. The flow restrictors can laminarize the flow rate of the fluid in the flow tube and thereby reduce flow turbulence and lead to optimal sensing performance of the flow sensor.