Melt this concentrated compound butter over grilled steaks, toss it with flame-kissed vegetables, or freeze some for a burst of summer flavor in the winter months. Use very ripe, very red tomatoes for best color and flavor.
Preheat the oven to 375 degrees and line a small baking sheet with parchment paper.
Place the tomatoes cut side down onto the paper. Roast until the skins are wrinkled and blistered, and the tomatoes are very soft, 30-35 minutes depending on the size. Remove from the oven and let cool.
Place the tomatoes and any juices in the bowl of a food processor. Process until very smooth and no seeds or large pieces of skin are visible, 2-3 minutes; stop and scrape down the sides of the bowl frequently.
Add the butter, salt, and pepper, and process until blended, stopping occasionally to scrape down the sides of the bowl, 2-3 minutes. Then, stir in the thyme and scrape into a small bowl and cover. (Or, make a log of butter by spooning it onto a sheet of waxed paper, folding the paper over the butter and rolling it gently until you have a sausage shape; twist the ends to seal.)
Refrigerate for at least 2 hours and up to 4 days. You can also wrap the log in foil and freeze for up to 3 months; thaw it in the refrigerator.