Arrange a rack in the middle of the oven and heat to 375°F.
Toss together the blueberries, 1/2 cup of the sugar, lemon juice, and coriander in a large bowl. If you’d like a more firmly set cobbler, mix in the cornstarch. Transfer the mixture to an 8×8-inch baking dish or divide among 8 (6-ounce) ramekins.
Mix the flour, remaining 3 tablespoons of sugar, baking powder, and salt for the cobbler topping in a separate large bowl. Pour in 1 1/4 cups of the cream and stir until the dough is shaggy. Add the remaining 1/4 cup cream and stir to combine.
Turn the dough out onto a well-floured work surface. Knead the dough just until it all comes together, about 30 seconds.
Pat the dough into a 1/4- to 1/2-inch thick rectangle. Cut into 8 square pieces or pat handfuls of dough into thick palm-sized disks if using ramekins.
If baking in an 8×8-inch baking dish, overlap the disks on top of the blueberries to make a “cobblestone” look. If baking in individual ramekins, top each ramekin with a disk of dough. If you have any extra topping, crumble it and sprinkle it over the surface of the cobbler.
Place the baking dish or ramekins on a baking sheet to catch drips, or place aluminum foil beneath it in the oven. Bake until the topping is turning golden-brown around the edges and the fruit filling is bubbling, 25 to 30 minutes for the individual ramekins, or 45 to 55 minutes for the 8×8-inch baking dish.
Remove from the oven and cool for at least 10 minutes before serving. Serve warm or at room temperature, topped with vanilla ice cream or whipped cream.