Once your raspberry puree has chilled, or at least come to room temperature, preheat the oven to 325 degrees. Grease and flour a bundt pan very well and set aside.
In a mixing bowl, whisk together the cake flour, baking powder, baking soda and salt. Set aside.
In another mixing bowl, whisk together the yogurt, milk, oil, lemon juice, lemon zest, and lemon extract. Set aside.
In your mixing bowl, beat the butter on medium until smooth. Add sugar and beat on medium/high until fluffy. This will take several minutes.
Add in the eggs one at a time, beating on medium just until combined after each. Scrape down the sides of the bowl and mix again only for about 10 seconds.
Add a third of the flour mixture and beat on medium until just combined. Add half the liquid mixture and beat just until combined. Add another third of the flour mixture, mix until combined. Add in the last half of the liquid mixture, beat, then add in the last third of the flour mixture and beat only until combined. Scrape down the sides of the bowl and mix again only for about 10-15 seconds.
Now take out 2 cups of the batter and add to a small mixing bowl. Add the 3/4 cup of cooled, strained raspberry puree to the 2 cups of regular cake batter and mix together with a whisk. Add in about two small drops of gel red food coloring to brighten the color a bit.
Pour half of the regular cake batter (from your large mixing bowl) into the prepared bundt pan. Smooth the batter.
Add the raspberry batter mixture to your pan and smooth.
Pour in the remaining regular cake batter over the raspberry batter and smooth.
Use the handle of a wooden spoon to swirl the cake batter well. Go around the pan multiple times to swirl very well. (If you don't swirl the batter enough, you will have large pockets of raspberry puree and the cake will not set up or bake throughout properly.)
Place in the oven and bake for approximately 55-60 minutes.
A toothpick inserted into the cake should come out with a few moist crumbs on it.
Once baked, remove from the oven and cool in the pan on a wire rack for about 25 minutes before turning the cake out onto a plate.
Allow the cake to cool completely before adding glaze.