Preheat the oven to 350F. Line a muffin pan with parchment paper liners.
In a medium mixing bowl, whisk together the ground flaxseed and water. Let stand for 5 minutes to thicken. Then, whisk in the remaining wet ingredients (i.e.,apple sauce, cranberries, coconut sugar, coconut oil, maple syrup, orange zest, orange juice, and vanilla).
In a large mixing bowl, whisk together the dry ingredients (i.e., spelt flour, almond flour, baking soda, baking powder, sea salt).
Add the wet mixture to the dry mixture and use a large wooden spoon to stir until just combined (read: no flour patches remain). Be careful not to overmix—spelt has a delicate gluten structure, so overmixing will result in dry, crumbly muffins. The batter should be quite thick and fluffy.
Divide the batter equally among the 12 muffin liners. (Since the batter is quite thick and fluffy, an ice cream scoop is great for this job, but you can also go the double-spoon route.)
If desired, garnish the top of each with a light sprinkling of slivered almonds. Press down lightly to ensure they stick to the batter.
Bake for 18 to 22 minutes, or until a toothpick inserted into the center of a muffin comes out clean.