Spiaggia’s Sarah Grueneberg heads into the “ Top Chef ” finals.

Chicago chef Sarah Grueneberg turned up the heat to win a cool victory on “ Top Chef ” Wednesday, securing her a spot in next week’s finals.In a fire-and-ice-themed elimination challenge, Grueneberg, 30, tapped into her Spiaggia roots and whipped up a winning handmade cannelloni pasta and cold — almost too cold — mousse. The Texas native will face off next week against another Texan: Paul Qui …