In a large mixing bowl, whisk together the flour, cocoa powder, sugar, and salt. Add cubed butter and cut into flour using your fingertips (in pinching motions) or a pastry cutter. Cut butter into flour until butter is evenly distributed and about pea-sized chunks (slightly larger chunks are ok).

Use a wooden spoon or spatula to combine milk with flour mixture until it's too hard to mix with a spoon. Use your hands to bring the mixture together into a soft dough. If the dough is too dry, add a tbsp of non-dairy milk at a time. Form into a rough ball. Wrap in plastic wrap and refrigerate for 1-2 hours (preferably, 2 hours).

While dough is chilling, prepare the filling. Over a double boiler on medium-low heat, add chocolate, vegan butter, coconut milk and sugar. Stir frequently until chocolate is melted and all ingredients are combined, about 2-3 minutes. Adjust heat as needed, to prevent chocolate from burning.

Take off the heat and whisk in peppermint extract. Allow filling to cool for about 30 minutes to set. This allows filling to thicken and be more spreadable.

Remove dough from fridge. Unwrap and cut dough into 2 equal portions. Wrap 1 portion and put back in fridge.

Roll 1 portion of dough into a 7.5 x 8.5" rectangle, about ⅛" thick. I suggest rolling it out a bit larger than that and then cutting to 7.5 x 8.5". Cut the dough into four rectangles. Use a ruler to help make this process easier and more precise.

Place a heaping tablespoon of filling into the center of 2 out of the four rectangles. Spread the filling around, leaving about ¼" space around the edges. Brush the edges with non-dairy milk, then place each empty rectangle on top of the one with filling. Use your fingertips to press firmly around the pocket of filling, sealing the dough on all sides.

Seal the edges by crimping with a fork, to prevent the sides from opening up while baking. Use the fork to poke holes in the center of the pop tart to allow steam to escape. Refrigerate the filled pop tarts while assembling the rest.

Repeat the last two steps with the other refrigerated portion of dough. Place the two completed pop tarts on the same baking sheet as the other filled ones. Refrigerate for 15 minutes. This chilling lets the pop tarts rest before baking.

Preheat the oven to 375°F.

Brush each pop tart with non-dairy milk. Bake for 24-26 minutes until edges appear set. Remove from the oven and allow pop tarts to cool on baking sheet for 5 minutes then transfer to a wire cooling rack. Cool completely before adding icing.

Whisk together all icing ingredients until smooth. Spoon and spread icing over the pop tarts. Sprinkle with crushed peppermint and enjoy!

Cover and store pop tarts at room temperature for up to 1 day or in the fridge for up to 5 days.