Baba au Rhum Pound Cake

To Make the Cake:

1. Place the milk into a heat-proof measuring cup.  Microwave for 20-30 seconds, or until the milk reaches a temperature of 105°F-110°F.  Add the turbinado sugar and the instant yeast and stir with a whisk to combine.  Allow the yeast to bloom for 6-8 minutes, or until a yeasted dome appears at the top of the milk.
2. Cut the butter into 1 tbsp cubes and set aside.  You won’t need them until the rest of the dough has come together, but you want them to be a soft room temperature before they’re added to the dough.
3. Add granulated sugar, salt, eggs, egg yolks, and about 320 g (~2.5 cups) of the all-purpose flour to the yeast mixture.  Using the dough hook of your stand mixer, begin kneading your dough.
4. Slowly add additional flour, about 1/8 of a cup at a time, until the dough starts to come away from the sides of the bowl.  You might not need all of the flour that the recipe calls for.
5. Once you have a slightly tacky dough that comes away from the sides of the bowl, spray non-stick spray on your hands and do the windowpane test.  The dough is ready to move on when  it is ever-so-slightly tacky to the touch, but not sticky.  Without non-stick spray on your hands, the dough will just seem undone.  It’s tricky like that!
6. Once the dough passes the windowpane test (the first time), begin adding the butter, one tablespoon at a time.  Allow the dough to fully incorporate each tablespoon of butter before adding the next one.  The bowl will likely get a little buttery during this process.  That is normal!  Just allow each tablespoon of butter to fully incorporate.
7. When all of the butter is incorporated, allow the dough to knead for another 3-5 minutes on low speed.  The dough is complete when it easily passes the windowpane test (again!) and is very pliable.
8. Spray the mixing bowl with a light coating of cooking spray, and allow the dough to rise, covered with plastic wrap (with a small hole to vent gases), for an hour and 5 minutes, or until doubled in size.  You can also use the finger poke test so that you can decide whether it needs a few more minutes.
9. Gently de-gas the dough by pressing down on it in the mixing bowl.  Use your fingers to shape the dough into a rough rectangle on your work surface, with the long side of the rectangle facing you.  You will not need additional flour to work with this dough.
10. Using a pastry brush, generously butter your bundt pan.  You do not need to use flour in your pan.
11. Use a rolling pin to roll the dough into a 12”x 16” rectangle, with the shorter side facing you.  
12. Roll the dough into a log, starting with the short side closest to you.  Press all seams together on the log.  
13. Form the log into a circle, then press the seams together from the two ends.  Try to make the circle as even in thickness as you can.  Don’t worry if one side is slightly thicker than the other though.
14. Check to make sure all of the seams are closed, and place the circle into the prepared bundt pan.  Cover loosely and allow to rise for 45-50 minutes, or until the dough has doubled in size.
15. While the dough is rising, set your oven to a true 325°F.  An oven thermometer is extremely helpful to help ensure that your oven is the correct temperature.
16. Once the dough has finished its second rise, place the dough into the 325°F oven for 25-35 minutes, or until the dough is deep brown.  You’ll know it is complete when it reaches an internal temperature of 200°F-210°F, and when it sounds hollow when thumped with your thumb.
17. Turn out the brioche onto a cooling rack immediately after baking.  Allow to completely cool before moving onto the next step.

To Make the Rum Reduction:

1. Add granulated sugar, salt, and water to a saucepan and bring to a boil.  Continue to boil until all of the sugar has dissolved.
2. Reduce to a very low simmer and add the rum and vanilla extract.  Reduce the rum sauce to the desired strength (1-5 minutes).  If you want this truly rummy, you don’t have to reduce at all.  Keep in mind, though, that it will have a very strong rum taste.
3. Place the pound cake back into the bundt pan.  Use a serrated knife to level the cake, if necessary.  Pour some of the rum reduction onto the bottom of the cake.
4. Place the cake back on the cooling rack, with parchment paper underneath the cooling rack.  Cut a 1.5” trench into the top of the cake and remove the extra cake from the trench.  Pour the rum reduction evenly over the entire cooled cake.

To Make the Pastry Cream:

1. Place the whole milk and vanilla bean seeds in a small saucepan.  Bring to a simmer and remove from the heat.  Set aside, covered, for 45 minutes.
2. Combine the sugar, cornstarch, and salt in a heat-proof bowl.  Add the egg yolks and whisk vigorously for about 90 seconds, or until the mixture is light yellow in color.
3. Create an ice bath in a large bowl.  
4. Slowly add the milk mixture and stir until combined.  
5. Place the entire mixture back into the original saucepan.  Whisk constantly, on medium heat, until the mixture starts to thicken.  It will take about 5-7 minutes, but it will thicken.  When you notice it starting to thicken, reduce the heat to medium-low and continue whisking.
6. Once it thickens, keep whisking constantly for one more minute.  
7. Remove from heat and add butter, whisking until the butter is completely incorporated.
8. Run the pastry cream through a fine mesh strainer in a medium bowl.  Immediately place plastic wrap on the top in order to avoid a skin, and place in an ice bath for 20 minutes, making sure not to submerge the pastry cream.  After 20 minutes, place the bowl into a refrigerator for about 90 minutes.
9. Whisk the pastry cream when you’re ready use it.  Pipe into the trench of your cake.  Garnish with fresh berries, if desired.
10. Enjoy!