Place the flour, baking powder, cinnamon, salt and chopped almonds into a bowl and whisk to combine the ingredients
Add the eggs and pureed prunes to the sugar and whisk until the mixture is smooth. Pieces of pureed prune will remain visible
Add the flour mixture in two batches and gently fold it into the batter until most of the flour is mixed in. The batter will be a little lumpy.
Next add the blueberries and gently fold them in and the remaining flour until no bits of flour remain.
Divide the batter between the muffin tins. Top the batter with 3 or 4 additional blueberries and some of the sliced almonds.
Bake the muffins for 18-20 minutes at 400F until the center of the muffins register at 200-205°F.
Serve the muffins warm with butter. Store leftover muffins in an airtight container for 2 days and in the refrigerator for 4 days.