To toast the hazelnuts: Preheat the oven to  350 degree F (177 degree C) and place the hazelnuts on a baking sheet.  Bake for about 15 minutes or until fragrant and the skins begin to flake.  Remove from oven and place a dish towel over the nuts.   Let the nuts sit (steam) for a few minutes and then rub the nuts in the towel briskly to remove the skins.  Let cool and then chop coarsely.

To toast the almonds:  In a 350 degree F oven bake the almonds for 8 - 10 minutes or until lightly brown and fragrant.  Let cool then chop coarsely. 

Then in a heatproof bowl over a saucepan of simmering water, melt the butter and chocolate.

Meanwhile chop the digestive cookies into small pieces (about 1/2 inch). 

Once the butter and chocolate are melted, remove from heat and stir in the digestive cookies, along with their crumbs, and the chopped nuts. 

Spread this mixture into a lightly buttered 8 - 9 inch (20 - 23 cm) tart or cake pan, cover, and refrigerate for several hours or until set.  Cut into slices.  Store in an airtight container.

Makes about 10 slices.