• Preheat the oven to 350 degrees F.
• Line a 9x9 square baking dish with parchment paper and spray with nonstick spray

Make the crumb topping:

• In a medium bowl, combine flour, coconut sugar, cinnamon, walnuts, and salt and mix briefly with a fork. Add the coconut oil and work it in with your fingers until small clumps form throughout, breaking up any large pieces of coconut oil. Refrigerate until ready to bake.

To make the cake:

• In a large bowl, beat the coconut oil and coconut sugar together for 1 minute. I do this in a standing mixer, but you can do it in a large bowl by hand. Add the vanilla, yogurt, and egg and beat until smooth.
• To the wet ingredients, add flour, baking powder, baking soda, cinnamon and salt. Mix with a wooden spoon or spatula until no clumps of flour remain.
• Transfer the batter to the prepared pan and smooth the top.
• Crumble the refrigerated topping over the batter evenly and bake for 30-40 minutes, until a tester comes out just clean. 35 minutes is perfect for me. The topping may look a bit wet in the middle, don't worry, it'll harden as it rests.
• Set cake on a wire rack to cool and drizzle with salted caramel glaze when ready to serve.

Make the salted caramel glaze:

• In a small bowl, whisk together the coconut milk and starch for 20 seconds until smooth.
• Add this to a small saucepan along with the coconut sugar and salt and bring to a boil, whisking continuously. Continue to cook at a low boil, whisking throughout, for 3-5 minutes until the mixture coats the back of a spoon. Taste, and add more sugar or salt as desired.
• Set aside the glaze as the cake bakes and drizzle when ready to serve.