Begin by adding cupcake liners to a muffin pan and set aside. If you don't have liners, spray the muffin pan with baker's spray instead.
In a small bowl, prepare the Bob's Red Mill egg replacer and then add some of the vanilla extract. Mix well and set aside.
In a food processor, combine the flour, egg replacer mixture, oil, and sugar. The dough should be soft and crumbly. Allow this mixture to blend until all ingredients are well combined.
Remove the dough from the food processor. Using a rolling pin, roll the dough into a flat disc shape (flatten the dough) and place into a zip lock bag or plastic wrap. Place in the refrigerator and allow to chill for 1 hour.
After allowing the dough to chill for an hour, preheat the oven to 350 degrees F.
Remove the dough from the fridge and roll into balls using your hands. Place into the cupcake liner and smash the dough into the liners. The dough should halfway fill up the liners.
Using your thumb, push down in the middle of the dough forming an indentation in the center. If you find it difficult to do this, you can do this with a spoon as well. Use a tsp of blackberry preserves in each center.
Bake the cookies for 20 minutes. Once the cookies are done, using a sieve, dust with confectioners' sugar. Allow the cookies to cool before serving.