Preheat the oven to 375°F and line a couple of baking sheets with parchment paper.
Whisk the water and flaxseed together in a large mixing bowl. Allow the mixture to sit for a few minutes to gel while you gather the rest of your ingredients.
Add ½ cup of the granulated sugar, the brown sugar, peanut butter, vegan butter, and vanilla to the bowl with the flax mixture, then beat everything together with an electric mixer on high speed for about 1 minute, until creamy.
Add the flour to the bowl, and sprinkle the baking powder, baking soda, and salt on top of the flour. Stir everything together until uniformly mixed and a soft dough forms.
Place the remaining ¼ cup of sugar into a small bowl.
Roll the dough into 1-inch balls, then roll the balls in the sugar. Place them on the baking sheets, spaced about 2 inches apart.
Bake the cookies for 10 minutes, remove the baking sheets from the oven, and transfer them to a cooling rack.
Wait about 1 to 2 minutes, just until the cookies are cool enough to handle, then use your thumb or a 1-teaspoon measuring spoon to form an indentation in the top of each one.
Allow the cookies to cool for 3 to 4 more minutes, then remove them from the baking sheets and transfer them directly to the racks to finish cooling.
Repeat the process to use up any additional dough, but make sure to let the baking sheets cool between batches.
Once the cookies have cooled, make the ganache. Place the chocolate chips into a large, heatproof bowl. Heat the coconut cream just to a simmer in a small saucepan on the stove or in the microwave, then pour it over the chips. Let them sit for 5 minutes, undisturbed.
Stir the mixture until the chips are completely melted. If you have a few stubborn pieces of chocolate, you can warm the mixture up for no more than 15 seconds at a time in the microwave.
Allow the ganache to cool until thick enough to pipe onto your cookies. This will take about 30 to 60 minutes in the fridge, stirring occasionally, or about 1 to 2 hours at room temperature (Note 2).
Cut a ¼-inch opening into the tip of a pastry bag, then fill the bag with the ganache. Pipe a dollop of ganache into the indentation in each cookie (Note 3).
Allow the ganache to set completely. This will take about 30 minutes in the fridge, or several hours at room temperature.
Serve and enjoy!