Preheat the oven to 400°F (200°C) and arrange 2 oven racks in the top and bottom thirds of the oven. Line 2 rimmed baking sheets with parchment paper.
In a small bowl, combine 3 tablespoons flour with the chocolate and pecans.
In the bowl of an electric mixer fitted with the paddle attachment, combine the remaining 4 cups flour, the sugar, baking powder, and salt. Add the butter and, with the mixer on low speed, blend until the butter is the size of peas, 2 to 5 minutes. Measure the cream in a 2-cup glass measuring cup, add the eggs, and beat until combined. With the mixer still on low, slowly pour the wet mixture into the dry mixture and mix just until blended. Add the chocolate and pecan mixture and once again mix just until combined. The dough will be very sticky.
Turn the dough onto a very well-floured surface and knead it a few times to be sure the chocolate and pecans are well distributed, adding a little flour so the dough doesn’t stick to the board. Flour your hands and a rolling pin and roll the dough 3/4 to 1 inch (18 to 24 mm) thick. You should see lumps of butter in the dough.
To cut the scones into squares or triangles, simply use a sharp knife to slice the dough into squares or triangles so there’s no wasted scraps. To cut the scones using a biscuit or cookie cutter, cut the dough with a 3-inch (8-cm) plain round cutter and place the scones on the prepared baking sheet. If desired, you can quickly and gently reroll the scraps and cut out more scones, handling the dough gently and keeping in mind that these will lack the same tender texture as the first batch since they’ve been handled a little more.
Lightly brush the top of each scone with egg wash, sprinkle with sugar, and bake, switching the pans halfway through, until the tops are lightly browned and the insides are fully baked, 20 to 25 minutes. Serve warm or at room temperature.