Preheat oven to 350 degrees and grease the sides and bottom of one 9x5 inch loaf pan.
In a large bowl combine 1 1/2 cups flour, baking powder, and salt. In another bowl, combine buttermilk, sugar, eggs, lemon zest, vanilla, vegetable oil, and poppyseeds. Whisk to combine and pour into the dry ingredients and combine.
Toss the fresh raspberries lightly in the 1 Tablespoon of flour to coat. Gently fold them into the batter. Pour into the greased loaf pan.
Bake for 50-55 minutes or until a toothpick inserted into the center comes out clean. Remove from the oven and let cool.
To make the lemon glaze, whisk together powdered sugar, lemon zest, lemon juice, and milk. Drizzle over the top of the cooled bread.