Preheat the oven to 350°F. Line a 12-muffin pan with paper liners.
Mix the sugar with flour, cocoa, baking powder, baking soda and salt. In a separate bowl, whisk together the egg, milk, melted butter and vanilla. Pour liquid ingredients into the dry and beat with a wire whisk for 2 minutes. Add boiling water and beat for another 2 minutes.
Scoop batter into prepared pan. Place 1/2 to 1 teaspoon jam into the center of each cupcake. Bake for 25 minutes or until done when tested with a toothpick. Let cupcakes cool on a wire rack. When completely cool, dust the cupcakes with confectioner's sugar, if desired.
Per Serving: Serving size: 1 cupcake, 140 calories (40 from fat), 4.5g total fat, 2.5g saturated fat, 30mg cholesterol, 180mg sodium, 23g carbohydrates, 2g protein.
Note: We've provided special diet and nutritional information for educational purposes. But remember — we're cooks, not doctors! You should follow the advice of your health-care provider. And since product formulations change, check product labels for the most recent ingredient information. See our Terms of Service.