I like to kick off the tomato-sauce-making season with roasted sauce. It's perfect when you have a fair amount of tomatoes, but now enough to justify going through all the effort of canning. I found this recipe years ago in Everyday Food (you're the best, Martha), and have made it countless times since.
I start by coating my pans with plenty of olive oil, thyme, salt & pepper, then layer sliced onions, and halved & cored tomatoes. Add a little more oil on top, and toss them in the oven.
Then I toss everything in a pot, and break out the emulsion blender. (This is the best thing ever -- and so cheap!)