Step 1: Preheat your oven to 350°F (175°C). Grease and flour a 9-inch round cake pan or line with parchment paper. If using almond flour, you can lightly grease only.
Step 2: In a large bowl, whisk together the pumpkin puree, Greek yogurt, eggs, maple syrup (or honey), melted coconut oil, and vanilla extract until smooth.
Step 3: In a separate medium bowl, combine the almond flour, pumpkin pie spice, baking soda, and salt. Whisk until well combined.
Step 4: Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix the batter.
Step 5: Pour the batter evenly into the prepared cake pan.
Step 6: Bake for 30-35 minutes, or until a toothpick inserted into the center comes out clean. The cake should be golden brown and spring back when lightly touched.
Step 7: Let the cake cool in the pan on a wire rack for 10-15 minutes before inverting it onto the rack to cool completely. Dust with powdered sugar if desired before serving.