Preheat the oven to 350ºF. Line 12 cups of a standard muffin pan with paper liners. Cover the dates with hot water and soak for 10 minutes. Drain and place in the bowl of a food processor fitted with the steel blade. Add milk, sunflower seed butter, and applesauce. Puree until smooth. Add the oat flour, sugar, cocoa powder, baking soda, peppermint extract, and salt. Puree to combine. Stir in the chocolate chips. Divide the batter among the lined muffin cups. Bake for about 25 minutes, rotating the pan once halfway through, until cracked on top and sunken in the middle. Cool for 20 minutes.
While the cakes cool, whip the cream with an electric mixer until soft peaks start to form, about 2-3 minutes. With the mixer running, add the peppermint extract. Add the sugar, a few tablespoons at a time, and whip to incorporate.
Serve the cakes warm, topped with the whipped cream.