Preheat the oven to 350F with a rack set in the middle of the oven. Use paper liners to line 18 cups of two 12-cup muffin pans.

Put the 1 cup + 2 tablespoons soymilk in a glass measuring cup and add the vinegar. Whisk to combine, then set aside at room temperature for at least 5 minutes to curdle.

Sift together the flour, baking powder, baking soda, cinnamon, and salt in a medium bowl.

In a high-speed blender, add the drained dates, oil, maple syrup, yogurt, soaking water, and curdled milk. Blend until the dates are pulverized. (This will take several minutes). Add the orange zest and blend for 5 seconds to mix it in. Pour the liquid into a large bowl.

Add half of the dry ingredients to the wet ingredients, stirring with a spatula until just combined. Add the remainder of the dry ingredients and stir again. Distribute the batter evenly among the lined muffin cups, filling the cups two-thirds full.

Bake for 28 to 30 minutes, rotating the muffin tins halfway through baking. (You may need to do this one muffin tin at a time for even baking.) The muffins are ready when a toothpick inserted into the center of a muffin comes out clean. Set the tins on wire racks for 5 minutes to allow the muffins to cool, then remove the muffins and place them on wire racks to cool completely.

Store in an airtight container on the counter for up to a week.