In a large bowl, mix the cottage cheese until smooth, blending first if it's lumpy.
Add 2 ½ cups (300 g) spelt flour, 5 ½ tablespoons (80 g) butter, 1 egg, and a pinch of salt. Mix with a spoon until just combined, no need to knead. Make sure the butter is soft or melted before adding.
Keep mixing until the dough comes together into a soft, sticky ball with no cheese curds left visible.
Turn the dough onto a floured counter and shape it into a log, roughly 10 inches (25 cm) long and 4 inches (10 cm) wide. Wrap tightly in plastic and chill for 20 minutes.
While the dough chills, set a large pot of water on the stove to boil, and halve and pit the plums. Cut only partway through each one, and if a plum is very ripe and hard to cut, just leave the pit in.
Once chilled, slice the dough into 8 equal pieces, about as thick as your thumb. Flatten each piece into a disc and place a plum in the center.
Fold the dough around the plum, pinching the edges to seal it completely, then roll gently between your palms to form a smooth, round dumpling.
Repeat with the rest of the dough and plums, dusting each finished dumpling lightly with flour as you go.
Lower the dumplings gently into the boiling water, giving them room to expand. Reduce to a gentle simmer, below medium heat, and cook for 15 minutes.
While the dumplings cook, melt 5 tablespoons (70 g) butter in a skillet and toast ⅔ cup (70 g) breadcrumbs over low heat, stirring often so they don't burn.
Once the dumplings float to the top, lift them out with a slotted spoon, roll them in the warm breadcrumbs, drizzle with honey and serve right away.