Whisk together flour and salt; set aside.
In another large bowl, add warm water, half of the sugar, active dry yeast, and allow it to bloom for 15 minutes.
Pour the warmed milk, remaining sugar, vanilla extract, and beaten egg into the bloomed yeast and mix well using a whisk, then add it into the flour mixture.
Using a dough hook attachment, mix the dough for 6 minutes.
Transfer the dough into an oiled bowl, then cover with cling film and allow the dough to rise for 2 hours.
Once risen, place the dough on a floured surface and slowly roll/stretch the dough but not too thin.
Cut the dough into several squares, then fry the dough beignets until golden at 350 degrees Fahrenheit. Transfer to a fried beignet into a rack lined with a paper towel.
Once cooled down, poke a hole on one side and pipe the ube halaya until it is filled.
Sprinkle with confectioner’s sugar and serve immediately.