2) Lightly grease the mini-muffin tins with vegetable oil spray. Place one teaspoon of slivered nuts in each of the muffin cups. Unwrap the caramel candies, cut each candy into quarters and place four quarters (one candy) in each of the muffin cups on top of the nuts in a single layer. Bake in the oven until the caramel is just melted and beginning to spread, about eight minutes. Be careful not to over melt the caramel or it will bubble, burn, and become too hard. Place the mini muffin tins in the refrigerator for five minutes to cool. Remove the nut clusters from the tins and set aside.
3) Meanwhile, melt the bittersweet chocolate in a double boiler over low heat. Whisk two to three tablespoons of double cream into the chocolate to slightly thin the chocolate for coating the clusters. Dip half of the nut clusters in the bittersweet chocolate and place on a parchment paper-lined baking sheet. Return the clusters to the refrigerator to harden, about 30 minutes.
4) Melt the white chocolate in a heatproof bowl over hot water, over a low heat. Whisk two to three tablespoons of cream into the chocolate to slightly thin the chocolate for coating the clusters. Dip remaining half of the nut clusters in the white chocolate and place on the parchment paper-lined baking sheet with the other chocolate-covered clusters. Return the clusters to the refrigerator to harden, about 30 minutes.