1/4 c. olive oil
1 med. onion, coarsely chopped (about 1 c.)
6-8 med. zucchini, trimmed, scrubbed, cut into 1/4" slices (about 8 c.)
2 cloves garlic, minced
4 c. heavy cream
Pinch of dried thyme
Salt
Freshly ground pepper

1. Heat oil in large heavy skillet over medium heat to rippling. Add onion; saute, stirring occasionally, until softened, 3 to 4 minutes. Add zucchini and garlic; reduce heat to low. Simmer, covered, until zucchini is very tender, but not browned, 25 to 30 minutes. Remove from heat. Stir in 2 cups of the heavy cream and the thyme; let cool slightly.

2. Place half of the zucchini mixture in blender or food processor; blend until mixture is very smooth. Transfer to large bowl. Stir in third cup of the heavy cream. Repeat procedure with remaining zucchini mixture and remaining 1 cup heavy cream. Force mixture through fine sieve. Add salt and pepper to taste. Refrigerate, covered, for several hours before serving.