In a small bowl stir to combine milk, water, sugar and yeast. Set aside for about 5 minutes for the yeast to react.TipMake sure the milk and water are lukewarm, not too hot or the yeast will die. The ideal temperature is about 34 °C / 93° F.
Add all-purpose flour and yeast mixture to a large bowl (or use a bowl of a stand mixer). Stir to combine using a wooden spoon. Add the egg, 1/2 tsp of salt and sour cream. Knead into a nice dough. Knead for about 3 - 5 minutes in a stand mixer, fitted with a kneading hook or for about 8 - 10 minutes on a lightly floured working surface. Then, add small cubes of butter at a time, letting each piece incorporate before adding the next. Knead into a nice, smooth and elastic dough.
Place the dough in a bowl and cover with a kitchen cloth. Leave the dough to proof at room temperature for about 1 hour or until doubled in size. Then, turn the dough out on a lightly floured surface, knead for a few seconds, then return the dough to a bowl. Cover and refrigerate for at least 6 hours or overnight (up to 24 hours).TipMake the walnut filling the same time and place it in the fridge as well.
Add brown sugar, white sugar, whipping cream and butter to a bowl. Place over medium-high heat and bring to a boil. Remove from the heat, stir in the chopped walnuts and ground hazelnuts. Let the mixture cool to room temperature, then place in the fridge for at least 4 hours or overnight.
Homemade Crescent Rolls with Walnuts
Remove the dough from the fridge. Turn out on a lightly floured surface and shape into a rectangle. Using a rolling pin, roll the dough into a 12 cm x 45 cm (5 inch x 18 inch) rectangle, thickness 3 mm / 0.12 inch. Keep your edges even and exact. Using a sharp knife or pizza cutter, cut the dough into 12 triangles, each measuring about 8 cm x 15 cm / 3 inch x 6 inch. Add one teaspoon of walnut filling to the wider part of the triange and roll into a crescent roll.
Place the crescent rolls on a baking sheet covered with parchment paper. Leave enough space between them to rise. Let them proof at room temperature for about 1 hour and 30 minutes or until doubled in size. Preheat your oven to 200°C / 390 °F.
Bake and Serve
Gently brush the proofed rolls with egg wash. Optionally sprinkle with a mixture of chopped almonds and cacao nibs. Lower the oven temperature to 190°C / 375°F. Place in the oven and bake for 15 minutes in convection oven or for about 20 minutes in a standard oven. Leave the baked crescent rolls to cool on a wire rack, then serve. Store in an airtight container for up to three days.