Preheat oven to 325 degrees F. Liberally grease a round 9" cake pan with vegetable-oil cooking spray and set aside.

In a large bowl, mix together the cake mix, applesauce, oil, water, juice and zest and beat with a hand mixer for about 1 minute or until combined. Fold in the poppyseeds. Pour the batter into the prepared baking pan. Bake for approx. 25-30 minutes or until a toothpick inserted near the center comes out clean or with moist crumbs. Cool completely in the pan before gently turning over onto a wire rack set over wax paper.

In a medium bowl, whisk together the glaze ingredients until smooth and pourable. You don't want it super thin, like water, but more syrupy and thicker, so adjust with more lemon juice or powdered sugar if needed. Drizzle the glaze over the cake and spread it out to the edges so the entire cake is covered. Serve garnished with raspberries and lemon slices, if desired. Serve immediately or store leftovers airtight at room temperature for up to 1 day.