Preheat the oven:
Set the oven to 350°F (175°C) and line a baking tray with parchment paper or lightly grease it.

Mix the wet ingredients:
In a large bowl, combine the softened butter, egg, maple syrup, and vanilla extract. Mix with a whisk or electric mixer until smooth.

Add the dry ingredients:
Stir in the almond flour, oat flour, baking powder, and salt until a dough forms.

Chill the dough:
Place the dough in the refrigerator for 10 minutes to make it easier to handle.

Shape the cookies:
Scoop about 1 tablespoon of dough and roll into balls. Place them on the prepared baking tray.

Create the thumbprints:
Flatten each cookie slightly and press a small indentation in the center using your thumb or finger.

First bake:
Bake the cookies for 5 minutes.

Add the jam:
Remove the tray from the oven and fill each cookie with 1–2 teaspoons raspberry jam.

Finish baking:
Return the cookies to the oven and bake for an additional 8 minutes.

Cool the cookies:
Remove from the oven and allow them to cool completely.

Prepare the icing:
In a small bowl, mix powdered sugar and almond milk until smooth.

Decorate:
Drizzle the icing over the cooled cookies and let it set before serving.