Wilt the spinach in a saucepan with a small amount of boiling water, then run under cold water to refresh, squeeze out the moisture, chop up the spinach then puree it with a hand held stick blender until smooth. (NOTE: make it really smooth in order to get a good green colour)
Beat the butter, peanut butter and sugar together until smooth and fluffy. Add in the spinach puree and almond extract and beat well. Sift in the flour and mix.
Turn the mixture onto a lightly floured surface and knead until it forms a soft dough. Wrap in clingfilm and chill in the fridge for 30 minutes.
Preheat oven to 350°F / 180°C. Line a baking tray with baking paper.
Roll tablespoonfuls of the dough into 4-inch long finger shapes and gently press the sides to create knuckles.
Use a knife to cut horizontal ridges for knuckles. Press an almond slice into the end of each finger.
Place the fingers onto the prepared baking tray and bake for 15 minutes or until the edges begin to turn very slightly golden.
Allow to cool for 5 minutes on the tray and then transfer to a wire rack to cool completely.
Dip the ends in the raspberry jam to create the look of severed fingers.
Cook's Tip: Be sure to puree the spinach to a paste so the colour of the witch finger cookies is evenly green.