Place the toasted slivered almonds and coconut flakes in the bowl of a food processor and pulse them together until the texture resembles coarse cornmeal.
Add 2 tablespoons maple syrup, 1 tablespoon melted coconut oil, ½ teaspoon cinnamon, and ¼ teaspoon Diamond Crystal kosher salt. Pulse until combined. The crumbs should stick together when you pinch some together between your fingers.
Line a 8-inch square pan with parchment paper and transfer the crust ingredients into the pan. Use an offset spatula to make sure the crust is evenly distributed on the bottom.
Place the crust in the freezer while you make the filling.
In a high speed blender, combine the soaked cashews, coconut cream or coconut milk, ¼ cup melted coconut oil, ¼ cup maple syrup, vanilla, and ¼ teaspoon Diamond Crystal kosher salt. Blend until silky smooth.
Pour the filling through a fine mesh sieve onto the crust. The sieve can break up any big air bubbles that form.
Cover the pan with a silicone lid, aluminum foil, or plastic wrap and freeze until solid (about 6 hours or overnight).
When you’re ready to serve the bars, take them out of the freezer, lift out of the pan using the parchment flaps, and cut into 16 squares with a knife or pastry scraper. If the bars are frozen too solid, let them thaw for a few minutes before cutting.
Before you eat the bars, go ahead and top them with extra toasted coconut flakes or melted dark chocolate, if desired. The coconut bars taste great straight from the freezer—almost like coconut ice cream bars! If you prefer the bars to have a softer texture, you can thaw them in the fridge before serving, Either way, they’re delicious!