Cream together butter, sugar substitute and vanilla with hand mixer.
Add almond meal, gluten-free flour blend and salt, stirring in until combined. Mix in milk.
Line rimmed baking sheet with parchment paper. Spoon dough into 6 little mounds, evenly across pan in 2 x 3 pattern.
Dip large spatula into hot water and spread dough over baking sheet (like spreading peanut butter) into even, thin layer. Clean off blade and dip again into hot water as needed.
Sprinkle almonds and coconut over dough, pressing in lightly to adhere.
Bake until starting to turn golden, approximately 18 minutes. At this time, briefly remove from oven to score into rectangles or diamonds* and then return to pant to bake 5 to 10 more minutes until golden brown.
Let pan cool on rack for 15 minutes.
In microwave-safe bowl, heat together dark chocolate chips and coconut oil 30-seconds at a time, stirring between, until melted and glossy. Use a spoon to drizzle free-form over cookie brittle. Let set, cut, and serve.
Store in airtight container. Makes approximately 24 pieces.
*May opt out of “scoring” step and bake straight through for 23 – 28 minutes, and then, after cooked, break into irregular-shaped pieces after drizzling with chocolate.