This frozen dessert is simple to make and tastes fantastic. An Oreo® cookie base is filled with toffee chunks and chocolate ice cream, then topped with toasted almonds. It's a great dish to make ahead of time.
Preheat the oven to 180 C / Gas 4. Scatter the almonds in a Swiss roll tin and toast until golden, about 10 minutes. Set almonds aside, but leave the oven on.
In a food processor, grind the cookies until they are coarse crumbs. Transfer crumbs to a bowl and stir in the flour. Stir in the 115g melted butter and toss to moisten.
In a large saucepan, combine the 300g butter, sugar, water, lemon juice and salt. Bring to the boil, stirring to dissolve the sugar. Cook uncovered, without stirring, over medium heat until it caramelises, about 8 minutes. Remove the caramel from the heat and stir in the vanilla, almond extract and 275g of the almonds. Pour the mixture into a buttered 23x33cm tin and set aside to cool.
Butter the bottom of a springform tin, leaving the sides unbuttered. Press the mixture onto the bottom of the tin. Bake until set, about 12 to 15 minutes. Transfer to a rack to cool. When base has cooled, place it in the freezer for at least 30 minutes.
In a microwave-safe bowl, microwave chocolate until melted. Stir occasionally until chocolate is smooth. Spread melted chocolate over the cooled toffee. Immediately sprinkle with 150g almonds. Freeze for 1 hour or until firm. Turn the toffee out onto a work surface and break it into 1.25cm pieces.
Let the ice cream soften very slightly in a large bowl. Stir briefly, just until malleable. Fold in the toffee. With a large rubber spatula, spread the ice cream into the base. Top with the remaining almonds. Place the pie in the freezer. When it has firmed up slightly, cover the top with cling film. Freeze until firm, about 6 hours.
Place the pie in the fridge to soften about 20 minutes before serving. Run the tip of a knife around the sides of the pie to loosen. Carefully remove the spring form tin. Cut into wedges with a knife dipped in hot water.