01 - Preheat oven to 350°F. Grease a 9x5-inch loaf pan and line with parchment paper for easy removal.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, salt, and poppy seeds until well blended.
03 - In a large bowl, beat butter and sugar with an electric mixer on medium-high speed until light and fluffy, approximately 2-3 minutes.
04 - Add eggs one at a time, beating thoroughly after each addition. Mix in lemon zest, lemon juice, sour cream, milk, and vanilla extract until fully incorporated.
05 - Gradually fold the dry mixture into the wet ingredients using a rubber spatula. Mix only until just combined to avoid toughening the cake texture.
06 - Toss fresh raspberries with 1 tablespoon flour to prevent sinking. Gently fold the coated berries into the batter, taking care not to crush them.
07 - Spoon the batter into the prepared loaf pan and smooth the top with a spatula for even baking.
08 - Bake for 50-60 minutes until a toothpick inserted in the center emerges clean. If the top browns too quickly, tent loosely with aluminum foil after 35 minutes.
09 - Let the cake cool in the pan for 15 minutes before transferring to a wire rack. Allow to cool completely before glazing.
10 - Whisk powdered sugar with fresh lemon juice until smooth and drizzle-consistency. Adjust with additional juice if needed.