Add cider to a large saucepan, set over medium-high heat and allow to simmer until reduced to 1/3 cup (keep a close eye on it during the last 10 minutes, it can burn. Keep a glass liquid measuring cup nearby to pour and measure, then return to pan as needed to reduce a little longer until it measured 1/3 cup), about 25 minutes (cook time will vary based on size of pan and burner temp, it might be less it might be more). Set aside to cool.
Butter and line and 8-inch baking pan with two sheets of parchment paper (one going each direction) leaving a 1-inch over hang on each end, and butter paper.
In a small bowl whisk together 2/3 cup of the cream, cinnamon, ginger, allspice, cloves, nutmeg and reduced cider. In a 3-quart heavy bottom saucepan combine sugar, remaining 1/3 cup cream, corn syrup and water.
Cook over medium-low heat, stirring constantly until sugar dissolves, then cook mixture, stirring occasionally, until mixture reaches 234 degrees on a candy thermometer. Remove from heat and slowly whisk in cream mixture.
Add butter and stir to melt. Return to medium-low heat and cook, stirring occasionally until mixture reaches 246 degrees on a candy thermometer.
Remove from heat and carefully pour caramel into prepared baking dish. Allow to rest at room temperature or in refrigerator until caramel is set. Sprinkle with Maldon then cut into squares or rectangles and wrap in wax paper. Store in refrigerator up to 2 weeks, bring to room temperature before enjoying.