Preheat the oven to 375 degrees F and line a muffin tray with 12 liners. (Or grease if not avoiding oil.)
Combine the soy milk and vinegar in a medium bowl and set aside to let curdle. Then, in a large bowl, add all the dry ingredients and mix well.
To the bowl with the now curdled soy milk, add remaining wet ingredients, except the blueberries, mix well and then pour the wet mixture into the bowl of dry ingredients. Mix until incorporated without over mixing the batter. Then fold in the blueberries.
Divide the mixture among the 12 muffin cups and bake for 18-22 minutes, or until a toothpick inserted in the center of a muffin comes out clean. Remove from the oven and let cool at least 10 minutes before removing muffins from the tray and transferring to a wire rack to continue cooling.
While the muffins are cooling, combine the glaze ingredients in a small bowl, if using. Start with 1 tablespoon of lemon juice and add more, only if you want to thin out the glaze. Once muffins are cooled, drop teaspoon amounts of glaze on the center of each muffin and let the glaze drip down the edges. Enjoy!
The muffins will keep at room temperature, covered or in an airtight container for 2-3 days. Or refrigerate to keep longer. You may also freeze a batch of muffins before glazing, and if you wish to glaze, thaw the muffins completely and glaze before serving.