Combine flour, sugar, and salt in a large bowl.

Cut the margarine into small pieces and add to the flour mixture. Mix by hand to form crumbs.

Add in ice water and mix just until dough forms a ball (don’t overmix). Wrap dough well in a piece of plastic wrap and seal. Refrigerate for one hour.

In a small saucepan, melt chocolate and praline paste over low heat. Stir until completely smooth. Set aside to cool.

Put walnuts and sugar into a food processor and process until finely chopped. Transfer to a small saucepan.

Add the water to the mixture. Bring to a boil over medium heat. Lower heat and stir constantly for three minutes until mixture forms a paste. Do not overcook, or your mixture will crystallize. Allow to cool completely.

Preheat oven to 350 degrees Fahrenheit (180 degrees Celsius).

Using a three-inch (eight centimeter) cookie cutter or the rim of a glass, cut circles in the dough. Try to cut each circle as close to the others as possible.

Place a scant teaspoon of filling in the center of each circle, filling half the circles with truffle filling, and half with nut filling. Pinch the edges together to form a triangle. Press the edges together tightly to prevent the hamantaschen from opening during baking.

Line a baking sheet with parchment paper and gently transfer the hamantaschen to it. Gather remaining dough, roll out again, and repeat the process.

Bake on the middle rack of the oven for 15–17 minutes. Allow to cool. Drizzle with chocolate syrup, if desired. Serve with a scoop of ice cream.

Roll out the dough between two large pieces of parchment paper until it forms an 18- by 13-inch (45- by 33-centimeter) rectangle, one-quarter-inch (one centimeter) thick. Remove the upper parchment paper from the dough for a moment, and promptly replace it. Turn over the dough and remove the now-upper parchment paper.