In a mixing bowl, combine the plain and bread flour. Add the oil, eggs, sugar, warm milk, purple yam, ube flavoring, yeast and salt. With a wooden spoon,or whisk, stir well after each addition until the dough forms a shaggy mass. Add just enough of the remaining flour (you might not use the whole 1/2 cup) to manage stickiness and stir until the dough comes together in the center of the bowl.

Lightly grease a kneading board with the oil, and turn the dough out.

Lightly grease hands with oil and knead the dough,  pushing the dough down and away from your body using the heels of your palms, until it's smooth and elastic but still somewhat tacky. 

Place the kneaded dough in a lightly oiled bowl and cover with a kitchen towel. Let rise for about 1 1/2 to 2 hours or until double in size.

Gently deflate the risen dough and form into a log. Cut the log vertically in half and then cut each half into  smaller portions.

Using the palm of hands, flatten each dough portion and place a piece of cheese or ube halaya filling in the center. Fold the dough around the cheese and form it into a smooth ball, tucking the ends under to seal.

Roll the dough in bread crumbs and arrange in a single layer at about 1/2 inch apart on a parchment-lined baking sheet. Cover loosely with a clean kitchen towel and let rise for about 30 to 60 minutes or until puffy and have doubled in size.

Bake in a preheated 350 F oven for about 20-23 minutes. Remove from the oven and allow to slightly cool as the filling will be hot!