Instructions

For the Cupcakes:

1. Preheat oven to 350 degrees F. Line muffin tins with cupcake liners.
2. Sift together all the dry ingredients in the bowl of an electric mixer.
3. In a medium bowl, combine all the wet ingredients using a whisk.
4. Mix the dry ingredients on low speed for 1 minute. Stop the mixer and add the wet ingredients. Mix for 2 minutes on medium speed and scrape the sides and bottom of the bowl. Mix for an additional minute on medium speed.
5. The batter will be thin. Divide evenly among the cupcake liners.
6. Bake for 12-15 minutes or until a toothpick inserted in the center comes out almost clean.
7. Cool cupcakes on wire racks completely. Meanwhile, you could start on the frosting.
8. While cupcake cools, make the filling.

To make the filling:

1. In a medium saucepan, combine the marionberries, sugar, lemon zest and juice. Simmer over medium-low heat until the marionberries are broken down and sauce thickens. Remove from heat and stir in the vanilla extract.
2. Divide into two and save one half as filling. The other half you can pass through a fine sieve and use in the frosting. I didn’t pass mine through a sieve.

For Marionberry Swiss Meringue Buttercream:

1. Whisk together sugar and egg whites in a heatproof mixing bowl set over (not in) a pan of simmering water. Whisk until warm and sugar is dissolved (mixture should feel completely smooth when rubbed between your fingers), 2 to 3 minutes. Remove from heat.
2. With an electric mixer on medium speed, whisk egg white mixture 5 minutes (using the whisk attachment). Increase speed to medium-high, and whisk until stiff, glossy peaks form and meringue has cooled (test by feeling bottom of the bowl), about 6 minutes.
3. Reduce speed to medium and switch to the paddle attachment. Add butter, one piece at a time, beating well after each addition. Beat in vanilla and saved marionberry filling into the batter. Whip for an additional minute.
4. Use immediately or store in an airtight container in the fridge for up to a week.