The night before you want to make the muffins, put the buckwheat flour, milk, vinegar, and salt in a medium mixing bowl, and stir to combine. Cover with a lid and let the mixture soak overnight 7-10 hours. This soaking process helps break down the phytic acid in the buckwheat seed making it easier on digestion over time.
The next morning, pre-heat your oven to 350 degrees, and spray a mini muffin tin with avocado oil spray or use mini muffin liners.
Stir in the rest of the ingredients to the soaked batter, and spoon the batter into your prepared muffin tin.
Bake the mini buckwheat pancakes at 350 degrees for 15 minutes (if you are making regular sized muffins, bake for more like 25-30 minutes). Let the muffins cool for a couple minutes, and then turn them out onto a cooling rack to cool completely. You can keep the muffins in an airtight container for 3-4 days, or in the freezer for months.