Adapted from Quick Recipes
1 ½ cups unsalted mixed nuts
½ cup superfine sugar or powdered sugar
½ cup whipping cream, plus 2 tablespoons
1 cup mascarpone cheese
2 tablespoons brown sugar
1 teaspoon vanilla extract
1 baked tart shell
Preheat the oven to 350 degrees. Spread the mixed nuts onto a baking sheet and roast in the oven for 5 minutes, or until they begin to brown. Set aside and allow to cool.
Meanwhile, place the superfine sugar in a small saucepan and stir constantly over medium heat until the sugar dissolves and turns golden, about 2-3 minutes. Turn the heat down to low and slowly stir in only 2 tablespoons of cream. Stir until the mixture is smooth and well combined and becomes a toffee syrup. Allow to cool slightly.
Beat together the mascarpone cheese, brown sugar, ½ cup of cream and vanilla in a bowl until smooth and creamy. If the mixture is runny, continue beating until mixture begins to resemble whipped cream. Pour into the tart shell and smooth out evenly.
Sprinkle the nuts over the cream mixture. Using a spoon, drizzle the toffee syrup over the nuts, zigzagging over the tart. Chill until ready to serve.