Line an 8 x 8 inch (20 x 20 cm) square baking pan with parchment paper, leaving overhang on two opposite sides to form a sling. Lightly grease the parchment with a thin film of coconut oil or butter.

In a medium bowl, combine the unsweetened shredded coconut, powdered keto sweetener, and fine sea salt. Stir to mix evenly.

In a small bowl or measuring cup, whisk together the full fat coconut milk or heavy cream, melted coconut oil or butter, and vanilla extract until smooth.

Pour the wet mixture over the coconut mixture. Stir until all of the coconut is evenly moistened and the mixture clumps together when squeezed in your hand. If it seems dry or crumbly, add 1 teaspoon of extra coconut milk at a time until it holds.

Transfer the coconut mixture to the prepared pan. Press it firmly into an even layer using clean hands or the back of a spoon. Cover with a piece of parchment and press hard with the bottom of a glass or measuring cup to compact the base.

Arrange the whole roasted almonds over the surface of the coconut layer in neat rows, gently pressing each almond into the coconut so it anchors but still remains visible on top.

Place the pan in the refrigerator and chill for 20 to 30 minutes, until the coconut layer is firm and cool to the touch.

While the base chills, melt the sugar free dark chocolate. Place the chocolate and 2 teaspoons coconut oil (if using) in a heatproof bowl set over a small pot of barely simmering water, stirring frequently until smooth, or microwave in 20–30 second bursts, stirring between each, until fully melted.

Remove the chilled pan from the refrigerator. Pour the melted chocolate evenly over the almonds and coconut base, using a spatula to spread it into a smooth, even layer that fully covers the surface.

Return the pan to the refrigerator and chill for 15 to 20 minutes, or until the chocolate is set and firm but not rock hard.

Use the parchment sling to lift the slab out of the pan onto a cutting board. Let sit at room temperature for 5 to 10 minutes if very firm, then cut into 16 bars with a sharp knife, wiping the blade between cuts for clean edges.

Store the bars in an airtight container in the refrigerator for up to 1 week, or freeze for longer storage.