How to Make It
Preheat the oven to 425° and lightly butter a 12-inch cast-iron skillet. In a large bowl, combine the 2 cups of flour with 3 tablespoons of the sugar and the baking powder and salt. Using a pastry blender, cut in the cubed butter until it is the size of small peas. Stir in the grated lemon zest, then stir in the heavy cream just until the dough is evenly moistened.
Turn the dough out onto a lightly floured work surface and knead several times, until it just comes together. Roll out the dough 3/4 inch thick. Using a 1 1/4-inch round cutter, stamp out as many biscuits as you can. Gently press the scraps together and stamp out more biscuits.
Mix the remaining 1 cup of sugar with the cardamom. Spread half of the cardamom sugar in a pie plate. Brush the biscuits with the melted butter and coat them all over in the cardamom sugar. Arrange the biscuits in the buttered skillet in a single layer. Drizzle any remaining butter on top and sprinkle with any cardamom sugar left in the pie plate. Bake in the lower third of the oven for about 25 minutes, until the biscuits are golden and risen. Let cool slightly.
In a medium saucepan, combine the remaining cardamom sugar with the berries. Bring to a boil, crushing the berries, and cook until thickened, about 5 minutes. Spoon the berry dunk into small bowls and serve with the monkey bread biscuits.