Preheat oven to 160°C (fan-forced) and line two baking trays with baking paper.
In a mixing bowl, beat the butter and brown sugar until light and creamy (2–3 minutes).
Add the honey, vanilla and egg yolk and mix until well combined.
In a separate bowl, combine the flour, baking powder, desiccated coconut and salt.
Add the dry ingredients to the butter mixture and mix until a soft dough forms.
Refrigerate the dough for 15 minutes to firm up slightly.
Divide the dough into 16 equal portions. Roll each into a short oval shape (about 4–5 cm long) and place onto the trays, leaving enough space between each (biscuits will spread).
Lightly flatten each biscuit, then gently drag a fork across the tops to create ridges (do not press down too hard).
Place the trays in the fridge for 5–10 minutes before baking.
Bake for 12–15 minutes, or until the biscuits are set but still pale.
Leave the biscuits on the trays for 5–10 minutes, then transfer to a wire rack to cool completely.
In a clean bowl, beat the butter, icing sugar and vanilla until light and fluffy. Add milk a little at a time until soft and spreadable.
Spread buttercream onto one biscuit, add a small spoon of raspberry jam, then sandwich with another biscuit.