A cooktop grate assembly includes a heat shield having an outer rim and a central plateau region offset from the outer rim by a connecting wall. The central plateau region defines an opening for receiving a burner assembly. A grate is positioned over the heat shield. The grate includes supports that extend over the central plateau region. A gasket is disposed adjacent to the heat shield. The gasket engages at least one of a base of the grate and feet of the supports to retain the grate in position relative to the heat shield.