Preheat your oven to 350°F (or 325°F if you’re using a bundt cake pan). Grease your loaf pan or muffin pan with cooking spray and line it with parchment paper to keep the cake from sticking.

In a large mixing bowl, cream 1 cup of unsalted butter with a mixer on medium speed for 1 minute. This makes the cake light and fluffy. You can also use melted butter if you prefer.

Add 1 cup of sugar to the butter and mix on low speed for 2 minutes until the sugar dissolves and the mixture becomes smooth.

Beat in the eggs one at a time, making sure each one is fully mixed in before adding the next. This helps make the cake nice and soft.

Mix in your sourdough starter discard, fresh lemon juice, lemon extract, and fresh lemon zest. These ingredients give your cake a bright lemony flavor. Adding a little sour cream will make the cake extra moist.

In a separate bowl, whisk together your flour mixture: 1 1/4 cups of all-purpose flour, 1 1/2 teaspoons of baking powder, and a pinch of salt. This is your dry mixture that will help the cake rise.

Slowly add the flour mixture to the wet ingredients and mix just until everything is combined. Be careful not to overmix! Fold in the poppy seeds with a spatula to spread them evenly throughout the batter.

Pour the batter into your prepared pan, making sure the top of the cake is smooth and even.

Bake the cake for 50-60 minutes if using a loaf pan, or 1 1/2 hours if using a bundt pan. You’ll know it’s ready when the top is golden brown and a toothpick inserted in the center comes out clean. If you're making muffins, bake for about 20-25 minutes.

Let the cake cool on a cooling rack in the pan for 1 hour before taking it out. This helps the cake hold its shape.

To make the glaze, mix powdered sugar, fresh lemon juice, and heavy whipping cream in a small saucepan over low heat until smooth. Drizzle the glaze over the top of the cooled cake for a sweet finish.