Your favorite sauce for orecchiette?

I like this one http://www.anitaliancanadianlife.ca/recipes/pasta-rapini/

Either pesto and peas, or:
Blanched and chopped rabe, crumbled sausage, red pepper flakes, garlic, and grated pecorino.

The well known Deborah Madison recipe which has chick peas as the key ingredient. It is an olive oil base with onion, garlic, sage and parsley, sprinkle of chilli flakes and lots of lemon zest to finish. Delicious with orecchiette.

I agree with the broccoli Rabe consensus.... lots of pamesean

Spring peas & parm.

http://www.food.com/recipe/orecchiette-with-sausage-and-greens-364683
I like this one, use whatever greens look good at the market.

I am also a fan of the simple broccoli rabe preparation, but sometimes a good tomato sauce and lots of cheese is just the ticket.

I love it with a simple bechamel, handfuls of grated asiago or parmesan, and either bacon or ham and some peas. I just rinse the frozen peas in a colander and dump them in. So comforting!

This is my own recipe which was a community pick https://food52.com/recipes/62811-ears-of-the-lombardian-consigliere

cauliflower, bacon, bread crumbs, garlic,

Something rustic, like this recipe: http://www.foodandwine.com/recipes/orecchiette-sausage-and-cherry-tomatoes I usually add spinach to everything and it would have parmesan Reggiano because I don't usually have provolone in the house.

Very simple, with broccoli or broccoli rabe, parmesan, small additions for seasoning (anchovy, red pepper....or not, as you like it).
There are many recipes out there to use as a starting point, e.g.
http://www.marthastewart.com/316912/spicy-orecchiette-with-broccoli