Preheat the oven to 350 degrees F. Spray three standard 6-cup muffin tins with nonstick cooking spray.
Fill a bowl with hot tap water. Place the raisins in the bowl to soak and plump.
In the bowl of an electric stand mixer, cream the butter and granulated sugar, beating on high until light and fluffy. Approximately 3-5 minutes. Once the butter mixture is fluffy, beat in the egg and caraway seeds.
Meanwhile, in a separate bowl mix the flour, baking powder, baking soda, and salt.
Scrape the mixing bowl with a rubber spatula. Then turn the mixer on low and alternate adding the flour mixture and the buttermilk until both are well combined.
Drain the raisins in a colander, tapping to remove all excess water. Scrape the bowl again. Then turn the mixer back on low and mix in the raisins.
Use a 3 tablespoon scoop to portion the batter into 18 muffin cups. Sprinkle the top of each muffin with Turbinado sugar.
Bake for approximately 20 minutes, until a toothpick inserted into the center of one muffin, comes out clean. Cool in the pans for 5 minutes, then gently dump out the muffins.
Once cool, store in an airtight container at room temperature for up to 5 days.