Gingersnap Crumble Ice-Cream Tart with Chunky Pineapple Sauce

Preheat oven to 350°F.

Melt butter. In a food processor grind gingersnaps to fine crumbs and add butter and sugar, pulsing until blended.

Sprinkle 1 cup (not packed) crumb mixture over bottom of tart pan and press with an offset spatula.

Sprinkle 1/2 cup crumb mixture around edge of pan and with your fingers press up side of pan. Carefully line shell with foil, folding over edge to cover crumbs completely, and add pie weights or raw rice.

Sprinkle remaining crumb mixture in a shallow baking pan.

Bake crumb mixture in lower third of oven 12 minutes and bake shell in upper third 20 minutes. Cool crumb mixture in baking pan on a rack and, when crumbs are cool enough to handle, with your fingers break up any large clumps. Cool shell in foil in tart pan on another rack 15 minutes. Carefully remove foil and weights or rice and cool shell completely (shell may be soft in center but will firm as it cools). Soften ice cream slightly and fold in half of crumb mixture. Spoon ice-cream mixture into shell, smoothing top, and sprinkle with remaining crumb mixture. Freeze tart until ice cream is firm, about 2 hours. Tart keeps, frozen and loosely covered, 3 days.

Cut rind from pineapple and quarter pineapple lengthwise.

Cut off core and cut pineapple quarters crosswise into 1/4-inch-thick slices. In a dry 2- to 3-quart heavy saucepan cook sugar over moderately low heat, stirring slowly with a fork (to help sugar melt evenly), until melted and pale golden. Cook caramel, without stirring and gently swirling pan, until golden.

Remove pan from heat and add pineapple (mixture will vigorously steam and caramel will harden). Simmer mixture, stirring, 5 minutes, or until caramel is dissolved, and cool sauce to room temperature. Chill sauce, covered, at least 2 hours and up to 5 days.

Serve tart with sauce.