1) Preheat the oven to 400°F. Lightly grease the cups of a standard muffin pan; or line with paper baking cups, and grease the paper cups.
2) Whisk together all of the dry ingredients, including the raisins.
3) in a separate bowl, whisk together the vanilla, vegetable oil, and whey.
4) Pour the liquid ingredients into the dry ingredients, stirring just to combine.
5) Spoon the batter into the prepared muffin cups, filing them full. A slightly heaped muffin scoop of batter is the right amount.
6) Sprinkle the tops of the muffins with coarse sparkling sugar or cinnamon sugar, if desired.
7) Bake the muffins for 18 to 20 minutes, until a toothpick inserted into the middle of one of the center muffins comes out clean.
8) Remove the muffins from the oven, and tilt them in their cups, so their bottoms don't steam. As soon as you're able to handle them, transfer them to a rack to cool. Serve warm, or at room temperature.
Yield: 12 muffins.