Special equipment: two 8-inch round cake tins with a removable base
Melt the chocolate in a double boiler.
Meanwhile, place the sugar and honey in a saucepan and heat gently, swirling the pan every few minutes, until the sugar has melted. Once melted, bring to a boil and cook for a few minutes until deep golden brown.
Remove the caramel from the heat and carefully add the butter and milk--removing from the heat will help minimize spitting when the cold ingredients go in. Whisk well until completely incorporated, then return to the heat.
Allow the caramel to bubble for 5 to 10 minutes, until thickened a little. (Note: It's very important to be extremely careful when working with cooked sugar such as caramel to prevent any possible burns to yourself or those around you. Cook on the back burner if you have kids, so the pot handles are unreachable. Resist the temptation of sticking your finger in to taste.)
Toss the popcorn with pecans in a large bowl, then tip into the caramel and stir until coated. Set aside about one-sixth of the caramel corn in a plastic freezer bag, and freeze. Divide the remainder between two 25-centimeter (10-inch) loose-bottom cake tins that have been greased on the bottom only with butter; press to even.
Stir the butter into the melted chocolate in the double boiler; pour over the two popcorn bases and spread evenly with a spatula.
Let the ice cream thaw for about 5 minutes, and then divide it between the cake tins. Level with a spoon dipped in hot water. Freeze overnight.
Remove the cakes from the freezer and stack one onto a cake stand. Spread with two-thirds of the lemon curd. Top with the second cake layer and spread with the remaining lemon curd. Remove the reserved caramel corn from the freezer and bash it while in the freezer bag to break apart; scatter over and around the cake. Garnish with mint sprigs and serve immediately.