My mother-in-law asked me to attempt to recreate her favourite blueberry cake in a gluten-free form for blueberry season. The first attempt was good, but the centre was slow to cook, leaving the edges a little browned for my liking. The second attempt was better, with delicate and tender sides and an evenly risen and browned top, but it was definitely a little more finicky. I made sure my butter and eggs were room temperature and I warmed the milk in the microwave. And I used fresh, not frozen, blueberries to reduce the cooking time. And I cooked the whole darn thing in a bain marie. It was nearly perfect cake, but if you really can't be bothered with the fussing, it will still be delicious -- a real, old-fashioned cake to serve with tea.
1/2 cup butter, softened
1 cup white sugar
3 large eggs, at room temperature
1 tsp vanilla
3/4 cup white rice flour
1/2 cup potato starch flour
1/4 cup amaranth flour
1/4 cup soy flour
1/4 cup sweet rice flour
1/4 cup tapioca starch
2 1/2 tsp baking powder
1/2 tsp xanthan gum
1/2 tsp salt
2/3 cup warm milk
2 to 3 cups blueberries
Grease and line with parchment paper a 9" square pan.
In a large bowl, whip butter until white. Cream sugar with butter until light and fluffy, several minutes longer than you think is reasonable. Add eggs, one at a time, beating well after each addition. Stir in vanilla.
In a separate bowl, whisk together flours and starches, baking powder, salt, and xanthan gum.
To the butter mixture, beat in flour mixture alternately with the warm milk. Fold in blueberries. Pour batter into prepared pan.
Place the cake pan in a larger pan; fill the larger pan with boiling water to halfway up the sides of the cake pan. Bake at 350F for about one hour (definitely a little more for frozen berries). A skewer poked into a crack in the cake's surface should test clean.
