In a standmixer fitted with the dough hook, whisk together bread flour, all purpose flour, and yeast. Add in ½ cup of lukewarm water and knead on low speed for 2-3 minutes. Add a little more water if the dough mixture has difficulty coming together.
Add 4 tablespoon of cubed and softened butter and knead on low for 5-7 minutes until incorporated. Increase speed to medium and knead for about 10 mimutes or until the dough is smooth. Transfer to a bowl that is greased with nonstick spray. Cover with plastic wrap for 45 minutes at room temperature.
Raspberry Banana compound butter
With a blender or food processor, puree' the fresh raspberries. Fold into the softened butter. Add in raspberry preserves, confectioner's sugar, vanilla extract and smashed banana. Set aside.
Rolling the dough
Transfer the dough to a lightly floured surface and cut into 8 portions. Working with 1 portion at a time, dust dough with a little flour and roll into ⅓ inch thickness. Spread ¼ of the softened compound butter over the dough. Roll the dough from one small end to the other as tightly as possible. Cut in half lengthwise. With the cut side facing out, twist it into a knot and tuck the ends underneath. Place in a greased muffin tin. Repeat until you have 16 knots.
Cover the pan loosely with plastic wrap or a kitchen towel and let it rise for 2-3 hours until fully doubled in size.
Preheat the oven to 400 °. Brush cruffins with egg wash. Bake for 15-20 minutes or they are golden brown on top.
In a large mixing bowl, mix together the cream cheese, heavy cream and granulated sugar until soft peaks form. Transfer to a pastry bag.
Just before serving, use a serated knife to cut a hole in the center of each cruffin. Fill with raspberry preserves and top with cream filling. Dust with confectioner's sugar.