Combine flour, baking powder, sugar, salt, and cardamom in the bowl of a food processor fitted with the metal blade. Whirl for several seconds to combine.
Remove the lid and scatter the butter evenly over the dry ingredients. Cover and process with 12 to 15 short pulses of about 1 second each. The mixture should resemble coarse meal and retain some peanut-sized lumps of butter.
Transfer the mixture to a large bowl and drizzle the heavy cream evenly over the top. Stir with a spatula until the dough begins to form. Turn the mixture out onto a large piece of plastic wrap. Use the plastic wrap to help you bring the dough together; fold the edges toward the center and press down until it holds together, taking care not to overwork the dough.
Roll the dough about 3/4 of an inch thick. Cut as many 3-inch hearts as you can. Re-roll the scraps and continue cutting hearts. Alternatively, pat the dough into a 3/4-inch thick circle; cut the dough into 8 wedges. Transfer cut scones to a parchment-lined baking sheet and bake in an oven preheated to 425° F until pale golden, about 12 to 15 minutes. Cool on a wire rack for at least 10 minutes before eating.