Preheat the oven to 350°F. Line a large baking sheet with parchment paper.

In a large mixing bowl, combine the oats, almond flour, espresso powder, cinnamon, baking soda, and salt. In a smaller mixing bowl, whisk the egg lightly. To the egg, add the oil, sugars, 1 mashed banana, almond butter, and vanilla extract, whisking until they are well combined. Pour the liquid ingredients into the dry, and whisk just until blended. Fold in 1 sliced banana, the walnuts (optional), and the raisins (optional).

Drop the batter in heaping tablespoons onto the prepared baking sheet to make eight large cookies. Space the cookies 2 inches apart and use your fingers to shape into rounds.

Bake the cookies for 13 to 15 minutes, until they are cinnamon brown. Let the cookies sit on the baking sheet for 5 minutes, then transfer them a wire rack to cool completely.

Make the icing: In a small mixing bowl, combine the almond butter, hot espresso or coffee, and both sugars, whisking until smooth. Transfer the mixture to a plastic sandwich bag and cut off a small tip from one of the corners to make a piping bag. Drizzle the icing over the cookies.

Cookies will keep in an airtight container for 1 day, or in the refrigerator for up to 3 days.