Make the jam by combining the raspberries, maple syrup and lemon juice in a small saucepan. Bring the mixture to a medium-high heat and cook, stirring frequently, until the raspberries have broken down. Remove from heat and stir in the chia seeds. Place in the fridge for 1 hour to thicken.
Make the cookie dough by adding the almond flour, gluten-free oat flour, maple syrup, coconut oil, vanilla and sea salt to a bowl. Mix in the bowl with a wooden spoon, then transfer the dough to a lightly floured surface and knead until uniform. Divide the dough into two, cover each piece with plastic wrap and place in the fridge for at least 20 minutes.
Preheat oven to 350F. Line two baking sheets with parchment paper. Working one piece of dough at a time, roll the dough to 1/4 inch thick between two sheets of parchment paper. Using a cookie cutter, cut an equal amount of cookies with a shape you desire cut out of the middle, such as a heart, star or triangle – this will be the top cookie), and with no shape cut out (these will be the bottom cookies). Transfer to the lined baking sheet and refrigerate for at least 15 minutes.
Bake the cookies in the oven for 8-12 minutes, until very slightly browned. Transfer to a cookie sheet and cool completely. Add about 1 tsp of raspberry jam to the bottom cookie. Gently sandwich the tops and bottoms together. Repeat with rest of cookies. Store in an airtight container at a cool room temperature for up to 24 hours, or in the refrigerator for several days. Makes about 25-30 cookies