Hibiscus Heart Donuts

Light and fluffy brioche donuts filled with a hibiscus pastry whipped cream, coated in hibiscus sugar

In a microwave safe measuring cup, heat the milk to 100°F / 38°C. Whisk in the yeast and the sugar. Set aside until the mixture begins to foam. (~5 minutes)
While waiting, add the flour, salt, egg, and butter to the bowl of a stand mixer fitted with the dough hook attachment. When the yeast mixture begins to foam, add it in to the rest of the ingredients.
Knead the dough on low speed for 1 minute to allow the ingredients to come together. Increase the speed to medium-high and knead for an additional 10 minutes, or until the dough passes the windowpane test. (This will happen after the dough has cleaned the sides and bottom of the bowl)
Once the dough is done kneading, butter the inside of the bowl, form the dough into a ball and place it back in the bowl, then cover the mixing bowl with plastic wrap. At this point, you could set the dough in the fridge to rise overnight, or continue to do this in one day. If doing in one day, set the dough in a warm area and wait for it to double in size (~1 hour.)
Before it's time to roll out the dough, make the hibiscus pastry cream.

In a small mixing bowl, whisk together the egg yolks, 50g sugar, salt, and flour until the mixture is light and fluffy. (It will be quite thick!)
In a medium sized saucepan set over medium heat, stir together the coconut milk and hibiscus powder. Continue to stir occasionally until the mixture comes to a simmer.
Once the mixture is simmering, remove it from the heat. While constantly whisking the egg mixture, use a small ladle to slowly pour some of the hot milk mixture into the eggs.
Now, while constantly whisking the coconut milk in the saucepan, slowly pour in the egg mixture until it's all combined.
Return the saucepan to the heat, and whisk constantly until the pastry cream thickens (this can vary from ~2-5 minutes)
(Optional) if you think there may be some cooked egg in your pastry cream, feel free to pass the pastry cream through a fine mesh sieve at this point.
Transfer the pastry cream to a bowl, and place plastic wrap right on top of the pastry cream. This will keep a layer from forming on top of the cream. Set it in the fridge to let it cool while frying the donuts.

Once the dough has doubled in size, punch it down to remove excess air, then transfer it to a clean, lightly floured surface.
Roll out the dough until it is ½" (~1 ¼ cm.) thick. Use a 3" heart cookie cutter to cut out the donuts, then re-roll the dough and cut out as many more donuts as you can.
Fill a large saucepan with at least 2" of vegetable or any neutral oil. Heat the mixture to 365°F / 185°C. Carefully place the donuts in to the fryer (3-4 at a time, depending on what your pan can fit). Fry the donuts on each side for 2 minutes, or until they are a deep golden brown.
Remove the donuts from the oil and toss them in the hibiscus sugar.

To finish off the pastry cream: beat together the heavy whipping cream and 1 tbsp. sugar until it reaches stiff peaks. Remove the pastry cream from the fridge, and gently fold the whipped cream into it.
Transfer the hibiscus cream to a piping bag fitted with a round piping tip.
Use a sharp knife to poke a hole in the top of each donut, then fill each donut with a generous amount of hibiscus cream.
Serve and enjoy!