Puree strawberries in a blender, or chop finely. Set aside.
Prepare cake pans. (I used a small 5 layer cake pan set from a craft store.) Lightly coat the pan/s with butter or coconut non-stick spray, dust with flour, and tap out excess. Set aside.
Sift the flour, baking powder, baking soda, and salt together. Set aside.
In a stand mixer, cream the butter and sugar. Next, slowly add in eggs and vanilla.
With the mixer on low, gently add dry ingredients until just combined then add the buttermilk (or milk) until combined. Do not overmix.
Add strawberry puree (strawberries mashed/chopped) and preserves by hand using a rubber spatula to combine.
Divide batter into prepared cake pan/s, spread evenly. The batter is pretty thick.
Bake 20 minutes at 350, or until toothpick comes out clean. Bake time will depend on the size of your pans. Small 6" pans are baked in 20 minutes, larger pans will take about 24 mintues.