Preheat your oven to 350°F (175°C) and grease a 9-inch round cake pan.

In a large bowl, whisk together all-purpose flour, granulated sugar, baking powder, baking soda, and salt.

In another bowl, whisk wet ingredients: flaxseed meal mixture, sourdough starter, vegetable oil, lemon juice, and lemon zest until smooth.

Gradually combine wet and dry ingredients gently until just mixed; avoid overmixing.

Pour batter into the prepared pan and smooth the top.

Bake for about 60 minutes, or until a toothpick inserted in the center comes out clean.

Allow cake to cool in the pan for 10 minutes before inverting onto a wire rack.

Whisk together powdered sugar and lemon juice to make the glaze; drizzle over cooled cake.

Slice and serve at your gathering, enjoying the vibrant flavors!