Gateau a la Sour Cream + Blueberry Custard

By garciamoss

Ingredients

• Brioche dough:
• 1 1/4 cup (175 grams) of all-purpose flour
• 3 tbsp (38 grams) of light brown sugar
• 1 1/4 tsp (4 grams) of instant dry yeast
• 1/2 + 1/8 tsp (4 grams) of fine sea salt
• 1 1/2 tbsp (29 grams) of whole milk
• 2 large (90 grams) eggs
• 5 1/2 tbsp (79 grams) of unsalted butter, softened
• Sour cream and blueberry custard:
• 1 scant cup (125 grams) of fresh blueberries + 1/2 tbsp of sugar
• 1/2 cup + 2 tbsp (162 grams) of sour cream or creme fraiche
• 1/4 cup (70 grams) of sweetened condensed milk
• 3 large egg yolks
• Zest of 3/4 lemon
• 1/4 tsp of vanilla extract
• Finely chopped almonds for sprinkling

Preparation

Step 1

To make the brioche dough: In a stand-mixer bowl, whisk together flour, light brown sugar, instant dry yeast and fine sea salt together (avoid direct contact between yeast and salt), then add the milk and large eggs and knead on medium-low speed until evenly incorporated. Scrape the bottom of the bowl thoroughly, then increase to medium-high speed and knead the dough for 5 ~ 6 min until elastic. The dough should be quite sticky but cohesive (partially sticking to the side of the bowl while the machine’s running, but able to retain its shape). If it’s too wet (unable to retain shape), add a couple more tbsp of flour and knead for another 2 min.

Turn the speed down to medium-low again, then start adding the softened butter 1 tbsp at a time (only add more when the previous tbsp has been thoroughly incorporated into the dough). Once all the butter’s been added, scrape the bowl and increase to medium-high speed. Knead for another 7~8 min until the dough is very shiny, smooth and elastic. You should be able to pick the dough up with the dough-hook, and it should slowly droop downward.

Cover the bowl with plastic wrap and let proof at a warm place for 1 ~ 2 hours until doubled (may take longer if temperature is cool). You can also let the dough proof for 1 hour at room-temperature then move into the fridge to ferment overnight (good for a next-morning brunch plan).

After proofing, scrape the dough onto a working surface, then stretch and fold the dough onto itself a few times (like folding a letter). Shape into a ball and roll it into a thick disk. Move the disk to the center of a parchment-lined 9″ (23 cm) round pie-dish (10″ could work, too), then with your hand, gently press down the center of the disk while expanding the dough outward, creating a rised/bumped up barrier around the edge. The center “basin” should be about 1/4″ (6 mm) thick, with the barrier about 1″ (25 mm) tall. Cover the pie-dish with plastic wrap and let proof again for another 20 min (40 min if the dough came out of the fridge). The dough should expand a little and look slightly puffier.

To make the custard and bake the brioche: Preheat the oven on 400ºF/200ºC.

Mix blueberries and sugar together and let sit for 15 min until it starts to emit a little bit of juice but not wet. Whisk together sour cream (or creme fraiche), sweetened condensed milk, egg yolks (save the egg whites for egg-wash), lemon zest and vanilla extract together until smooth. Gently press down the center of the dough-basin again to create more space if needed, then carefully pour in the sour cream-custard, then scatter the blueberries into the custard. Beat the egg-whites until foamy then brush it onto the edges of the dough. Sprinkle with finely chopped almonds and bake in the oven for 20 ~ 25 min until golden browned on top.

Let cool for at least 20 min before cutting.