Preheat oven to 350°F and line an 8x8 pan.

Mix almond flour, coconut flour, sweetener, and salt.

Cut in butter until crumbly, then stir in egg and vanilla to form dough.

Press two-thirds of dough into pan for the base.

Bake base 12 minutes until pale golden.

Mash raspberries and stir in lemon juice, zest, and chia or gelatin.

Spread fruit layer over baked base, then crumble remaining dough on top.

Bake 15 to 18 minutes until set. Cool completely, chill, and slice.