Preheat oven to 425°F. Line your muffin pan with cupcake liners and lightly spray with non-stick spray.
Zest and juice one large orange or two small oranges.
In a large mixing bowl or stand mixer, add the wet ingredients, including honey, sour cream, eggs, orange juice, oil, orange zest, vanilla extract, and almond extract. Mix with an electric hand mixer or whisk until well combined.Add the dry ingredients, including oat flour, almond flour, tapioca flour, baking powder, baking soda, and salt. Stir until evenly mixed. Allow the batter to rest for five minutes. Gently fold in the frozen or fresh blackberries until evenly distributed throughout the batter.
Fill the muffin cups nearly full with batter with a large cookie scoop or ice cream scoop. Allow the batter to mound higher in the middle. Add several chopped blackberry pieces to the top of each muffin.To get a higher dome on the muffins, bake at 425°F for 5 minutes. Leave the muffin tin in the oven, reduce the heat to 350°F, and bake for 12-14 minutes or until the muffin tops are lightly brown. Allow to cool on a wire rack. In a small bowl, whisk together the powdered cane sugar and orange juice until smooth. Adjust the consistency by adding more sugar or juice as needed. Once the muffins have cooled, drizzle the orange glaze over the tops of the muffins and add some additional orange zest.