Preheat the oven to 325˚F. Spray a 9x5 inch loaf pan with cooking spray. Line the inside of the pan with parchment paper. Set it aside for later.
In a bowl, add in the flour, baking powder, baking soda, poppyseeds, and kosher salt. Whisk until everything is evenly distributed.
In a separate bowl, add in the butter and sugar. Cream the ingredients together with a rubber spatula until fluffy and well combined. Whisk in the eggs and vanilla extract and mix until combined. Then add in the lemon zest, lemon juice, greek yogurt, and whole milk. Mix until everything is well incorporated.
Add the flour mixture into the bowl of wet ingredients. Mix with a rubber spatula until everything is almost fully combined. Then fold in the raspberries and mixed until combined.
Pour the batter into the prepared loaf pan. Shake the pan for a few seconds to even it out. Place the pan on top of a baking sheet and bake it in the oven for 1 hour 30 minutes or until fully cooked. When a toothpick is inserted into the center of the cake it should come out clean or with a few crumbs. Remove the cake from the oven and allow it to cool in the pan for 5-10 minutes. Then remove the cake from the pan and place it onto a wire rack to cool completely.