Preheat your oven to 400 degrees.
Using your fingers, work the shortening in with the flour in a large bowl until the flour appears crumbly, about the size of little peas. Stir in the buttermilk with a wooden spoon. Start with 3/4 cup & add a little more if need be.
Lightly dust your countertop with a little flour. Pat your biscuit dough into a large rectangle.
Spread the nutella over the biscuit dough, leaving about 1/2" to 1" uncoated perimeter around the edges. Sprinkle with the raspberries.
Starting with the long end, roll up into a long roll - like you would do with homemade cinnamon rolls. Slice into 1.5 to 2 inch rounds and place in a baking pan. Brush with a couple tablespoons of melted butter.
Bake at 400 degrees for about 15-18 minutes, or until the tops are lightly browned. Sprinkle with powdered sugar if you like.