Preheat oven to 350℉. Place pecans on a rimmed baking sheet. Toast for 5 minutes, then stir and toast an additional 4 minutes until the pecans are fragrant. Set aside.
Line 1-2 baking sheets with parchment paper and set aside.
In a heavy-bottom saucepan, add the sugars, butter, half and half, and cream. Place over low heat, stirring with a wooden spoon to combine as the butter and sugars melt into the cream. Once melted and combined, increase heat to medium.
Continue to stir slowly until the mixture comes to a vigorous boil (it will simmer first and then the boil will become more rapid). It will start to boil around the 225℉ mark.
Once it is rapidly boiling, stop stirring. Boil until the mixture reaches the soft ball candy stage on the thermometer, which should be between 236-240℉ and take 3-4 minutes from the initial boil. Remove from heat and stir in the boiled cider. Let cool for 2 minutes. Stir in the pecans and then stir vigorously until the mixture turns cloudy and thickens to a consistency of thick syrup, about 2 minutes.
Working quickly, spoon the hot mixture into mounds on the prepared baking sheets lined with parchment. You should get 14-16 pralines out of this batch. Let the pralines cool for 15-20 minutes or until they are easily removed from the parchment. They are delicious served slightly warm!
Pralines are best within a day or two of making them. As each day passes, they will become dry and crumbly. Store at room temperature in an airtight container, or freeze the pralines between layers of parchment up to 3 months, thawing at room temperature for 1-2 hours before serving.