Step 1Heat the oven to 350 degrees.
Step 2Halve the tomatoes lengthwise, and place them, skin-side-down in a roasting pan. Scatter the garlic and thyme sprigs over the tomatoes, and season with several grinds of black pepper, or to taste.
Step 3Layer the bacon over the tomatoes, placing the strips, one at a time, over the tomatoes, slightly overlapping them if necessary.
Step 4Place the roasting pan in the oven and roast for 1 hour.
Step 5Increase the heat to 400 degrees and continue to roast until the bacon crisps and browns on top, an additional 10 to 15 minutes. Remove the pan from heat.
Step 6Carefully remove the layer of bacon (save the bacon for snacks or set aside for another use). Taste a bite of tomato and check for seasoning. Sprinkle over 1 teaspoon salt, or as needed (saltiness will vary by brand of bacon, and more or less salt may be needed for the tomatoes). Gently turn the tomatoes over in the pan (cut-side down), and place the pan on the stove. Bring the liquid around the tomatoes to a gentle simmer over medium-low heat and simmer for 3 to 5 minutes to distribute the seasoning and flavors. Remove from heat.
Step 7Place the tomatoes in a glass jar or bowl. Cover with the remaining liquid, gently pressing the tomatoes down so they are submerged. Set aside until cool.
Step 8Cover and refrigerate the tomatoes until ready to use, and then warm on the stovetop before using. The confit will keep for up to 10 days, covered and refrigerated.