Peel the aubergine and cut crosswise into slices, 1/2 inch thick (12mm).

Preheat the broiler.

Arrange aubergine slices on a rack in a broiler pan and broil till lightly browned, 3-4 min.

Turn and broil second side about 2-3 min.

Transfer the aubergine to a cutting board an cut into small pieces and let cool.

Place aubergine on towels to drain off any excess liquid.

In a food processor bowl, fitted with the metal blade, combine aubergine, walnuts and 1/4 cup of the ricotta cheese.

Puree till smooth.

Transfer to a bowl and add in the remaining ricotta and parmesan, parsley, basil and sage.

Stir till blended.

Cover and chill for at least 3 hrs, at most 24 hrs.

Make the pesto in a food processor fitted with blade.

Chop basil leaves, pine nuts, minced walnuts, garlic, and parmesan cheese in the food processor.

Add extra virgin olive oil and pulse until a paste forms.

Season pesto after you taste it.

Just before using the filling, taste it and season with salt and pepper.

Make ravioli using 1 teaspoon of filling per pillow and seal with water.

Set aside ravioli on rack to dry for 1 to 2 hrs.

Gently cook ravioli in plenty of boiling water till al dente, 3 to 4 min.

Meanwhile, heat butter, the tomato sauce and the pesto in a pan.

Drain pasta and serve in a warmed, shallow bowl, with heated pesto-sauce an freshly grated Parmesan.