In a large saute pan, heat 1/2 cup olive oil on medium high heat. Sweat the squash and the onion together until very soft.
In a food processor, puree the squash mixture. Drain well to get out extra moisture. Put in a bowl with cheese, butter, bread crumbs, eggs, scallions, thyme, salt, and pepper. Mix well. Let it stand for 1 hour, refrigerated.
Roll into about 2-inch balls. Lightly dredge in the flour and fry in the remaining olive oil and butter until golden brown.