Preheat the oven to 350F and line a muffin tin with muffins liners.
In a large bowl, whisk the wet ingredients together: melted butter, maple syrup, applesauce, eggs, and vanilla extract.
Add the dry ingredients to the wet ingredients: sifted einkorn flour, baking powder, baking soda, cinnamon, and salt. Stir to combine. (To sift the einkorn flour, add the flour to a sieve and gently tap to sprinkle the flour into the bowl--this removes clumps that can form in the batter.) Let the batter rest for a few minutes while you mix the cinnamon roll topping.
In a small bowl, combine the cinnamon roll topping ingredients: brown sugar, butter, cinnamon (1 tablespoon + 1 teaspoon), vanilla, cardamom.
Fill the muffin liners about 1/3 full with muffin batter. Then add a scant 1/2 teaspoon of cinnamon roll topping to each muffin.
Add the rest of the batter evenly to each muffin.
Top off each muffin with another scant 1/2 teaspoon of topping.
Bake the muffins for 18-22 minutes, or until a toothpick looks clean and free of wet batter (ignoring any topping on the toothpick).
Let the muffins rest in the tin for 10 minutes before removing to a rack to cool completely. Store the muffins on the counter for 1-2 days, in the fridge for up to 5 days, or in the freezer for up to 3 months.
Sub whole wheat einkorn: If you want to use whole wheat einkorn instead of the all purpose einkorn flour called for in this recipe, reduce the flour by about 1/4 cup. The batter should be thick once all the ingredients are incorporated. If you find the batter is too runny, add in additional flour until you reach a thicker consistency.