In a separate small bowl, toss the chopped ramps with the walnut or olive oil and set aside.

Lightly toast the chopped walnuts in a naked frying pan over a low flame and set aside.

Place the flour in a mixing bowl. Make a well in the middle of the flour and sprinkle in the salt.

Sprinkle the yeast in the well and pour in the lukewarm water. Let the yeast dissolve for a few minutes

Add the buttermilk to the mixture and use your hands or the dough hook of your mixer to knead everything into a dough.

Add the ramps in oil to the dough and knead once more to thoroughly incorporate.

Add the walnuts and knead until just combined.

Cover the bowl with a clean dishcloth and let it stand in a warm place for 20 minutes.

Line a baking sheet with parchment paper.

Turn the dough out onto a floured workspace. Knead the bread hard until the dough loosens up and the ingredients are well combined.  Alternatively, use the dough hook of your mixer.

Shape the dough into a loaf on the parchment paper. Brush the loaf with the egg yolk. Use a sharp knife to create diagonal cuts 1/8 inch deep across the top.

Place the baking sheet in the refrigerator for 20 minutes.

Preheat the oven to 200 degrees F.

Place the bread in the oven and cook for 30 minutes.

Raise the oven temperature to 375 F and bake for another hour.

Remove from the oven, and transfer to a wire rack to cool.