Prep your space: Preheat to 180°C / 350°F. Grease an 8-inch round cake tin and line the bottom with parchment paper. Trust me, don’t skip the parchment unless you like playing cake roulette.
Cream the base (2-3 mins): In a medium bowl, beat the room-temperature salted butter and caster sugar together until pale and fluffy.
Add the wet ingredients: Whisk in the eggs one at a time, followed by the fresh lemon juice and that fragrant lemon zest. Rubbing the zest into the mixture releases all those gorgeous essential oils.
Mix the dry ingredients: In a separate bowl, whisk together the gluten-free plain flour, baking powder, bicarb soda, and xanthan gum to ensure everything is evenly distributed.
Combine gently: Stir the dry ingredients into your wet mixture until a smooth batter forms. If the mix looks a little too thick or stubborn, fold in an extra tablespoon of your reserved tin blueberry juice to loosen it up.
The berry fold: Very gently, fold your drained tinned blueberries into the batter using a spatula. Try not to overmix, or you’ll end up with a completely purple cake!
Bake to perfection: Spoon the batter evenly into your prepared tin. Bake for 35 to 40 minutes, or until the top is golden and a toothpick inserted into the center comes out clean.
Cool completely: Let the cake cool in the tin for 10 minutes, then transfer it to a wire rack [don’t cut it yet, I know it’s tempting!].
Glaze and dazzle: While the cake cools, whisk together the icing sugar, lemon juice, and the reserved blueberry juice until a smooth, brightly colored glaze forms. Drizzle it generously over the cooled cake and top with extra lemon zest for that gourmet pop.
