Put the oven rack on the upper third of the oven. Heat the oven to 400 degrees F. Stack two baking sheets together and line the top sheet with parchment paper.
In a food processor, combine the flour, baking powder, sugar and salt.
Process about 10 seconds to blend dry ingredients.
Add in the butter chunks and process with three pulses for 6-8 seconds per shift. Mixture should be fine and grainy with no big chunks of butter.
Transfer the mixture to a large mixing bowl. Make a well in the center and add the egg, vanilla and 3/4 cup of the cream as well as the scrapings of the vanilla bean. Stir with a fork. Stir the mixture briskly but firmly about 10-14 times to bring it together somewhat, bringing the dough into the center of the bowl and turning the bowl as you do so. Then knead briefly with hands to pull mixture together a bit more, about 5-6 times, until you have a rough dough that holds together but is a touch ragged looking. This is when to add the additional 1/4 cup more cream, if necessary.
Sprinkle about 1/2 cup of sugar on a work surface.
Then, using your hands to continue mixing, turn out the dough onto the sugared work surface. Blend with your fingertips, kneading or squeezing dough gently but firmly to get a soft dough that holds together, pressing it gently in the sugar on the board in order to help knead the dough but have the sugar adhere at the same time. Once you have a mass, firmly knead the dough 6-8 times.
Let the dough rest 3-5 minutes.
Divide the dough in two and pat it into two discs, each about 1-inch thick and 6-8 inches in diameter. Cut the discs into four wedges.
Set the scones on the lined baking sheet, spacing them evenly. Brush them with melted butter.
Bake until the scones are nicely browned on top, 17 to 20 minutes.