In a large bowl, sift together the dry ingredients: oat flour, cocoa powder, baking soda and salt. Set aside.
Add coffee and milk to a microwave-safe bowl. Heat in 10-second increments until just warm. This will prevent the melted coconut oil from solidifying once mixed with these liquids.
In a medium bowl, whisk together all wet ingredients: coffee, milk, coconut oil, sugar, maple syrup and vanilla. Whisk until well incorporated.
Add wet ingredients to dry ingredients. Whisk until just incorporated, making sure no flour patches remain. Fold in raspberries and chocolate chips. Optionally, dot the tops of each muffin with raspberries and chocolate chips.
Pour batter evenly into prepared muffin pan—filling each cup about 3/4 of the way for a higher quantity of smaller muffins, and all the way to the top for a lower quantity of larger muffins with big, domed tops. Bake for 16-22 minutes. Mine took 20 minutes for larger muffins.
Place muffin pan on a cooling rack to cool for 30 minutes. Remove muffins from pan and continue cooling on rack until completely cool, 1-3 hours. To make Chocolate Drizzle: Add Chocolate Ganache Drizzle ingredients to a small, microwave-safe bowl. Heat in 20-second increments until softened and smooth, stirring in between each increment. Spoon or pipe ganache over muffins. Enjoy!
*If using homemade oat flour, make sure to sift the flour to remove coarse bits of oats that could create grainy, overly moist muffins without domed tops.
Storing instructions: Best the first day. Loosely cover muffins and store at room temperature for up to 2 days, or in the refrigerator for up to 5 days. Or, freeze immediately after cooling for 1 month. Allow to thaw for 10-20 minutes before enjoying or heat in 10-second increments in the microwave until just warm.