Paris Hilton knows how to splurge in style. While the “Cooking With Paris” star, 40, has a closet full of designer duds, she revealed her “biggest splurge” to date is a custom pink Hermès Birkin bag covered with crystals. Hilton gave fans a glimpse into her extensive wardrobe Thursday for an Elle closet tour, recounting her most memorable — and expensive — outfits and accessories. “For my biggest splurge, this is a custom-made Birkin bag,” she said, holding up the rare Rose Tyrien-colored purse. “I love Hermès, and I love this bag.