First we will begin making the dough. Heat up milk in a small sauce pan until it begins to simmer. Remove from heat and add sugar and salt and stir. Let it cool down to lukewarm to the touch. While milk is cooling, proof the yeast by adding the warm water and yeast in a small bowl and stirring together. Let it activate by setting it aside for 10 minutes.
Once milk is cool, add to a large bowl, along with 3 ½ cups of the flour, 2 tablespoons of oil, eggs, and yeast mixture. Stir together with a wooden spoon until combined. The dough will be very thick but still pretty wet and sticky.
Place ¼ cup of flour on the surface of your counter. Place dough on top of it and begin kneading the dough with the flour until all the flour is mixed into the dough. Keep kneading for about 4-5 minutes until the dough is smooth and elastic. If it starts to stick to the counter, add a little more flour. Once you finish kneading, shape into a ball. Lightly grease another large bowl and place the ball of dough into bowl. Cover with a kitchen towel and let it rise for 1 ½ hours, where it will be double the size. I like to place mine in the microwave to keep it away from any cool draft from the A/C.
Once dough has risen, punch it down with your fist and remove from the bowl. Lightly dust your counter with flour and place the dough on top. Cut dough into 4 even slices. Cut each slice into 2 even pieces. You should have 8 even pieces. Roll each piece into an even ball. Place on a baking sheet. Cover with plastic wrap and let rise for another 30 mins.
While the dough rises again, make the vanilla creme anglaise. Heat milk, cream and vanilla bean paste in a small sauce pan until scalding. While it heats, whisk egg yolk, sugar, and vanilla in a medium bowl. Slowly mix scalded milk into egg yolk mixture. Return to the sauce pan and heat just until the miture coats the back of the spoon. It will have thickened a little but still be runny. Remove from heat to let it cool. Strain the sauce to remove any lumps before serving.
Once the buns are done rising, place a large braising dish or skillet on the stove (make sure you have a lid for the pan). Add milk, sugar, and butterand whisk together. Heat over medium-low heat until the butter has melted. Add all 8 buns to the pan with the liquid. If all the buns don't fit, split into two batches or two pans. Cover and let steam for 20 minutes. Remove from heat and add the vanilla sauce over the top or to the serving dish. Serve dumplings with blackberry preserves.