Preheat the oven to 350°F (175°C). Cut each cherry tomato in half and place cut-side up in a large oven-proof baking dish.
Whisk together a splash of olive oil, 1 tablespoon brown sugar, and a few pinches of salt; drizzle over the tomatoes and toss gently to coat. Roast for about 45 minutes, until the tomatoes have shrunken and are sweet.
Bring a large pot of salted water to a boil and cook the penne according to package instructions until al dente. Reserve 1 cup of pasta cooking water, then drain the pasta.
Meanwhile, make the sun-dried tomato pesto: in a food processor pulse the sun-dried tomatoes, garlic, red pepper flakes, olive oil, fresh thyme, and salt until a textured crumble forms.
Add the pine nuts to the food processor and pulse a few times more to incorporate them into the pesto; set the pesto aside.
In a large mixing bowl combine 1/2 cup of the reserved pasta water with about two-thirds of the sun-dried tomato pesto. Add the drained pasta and toss gently, adding more hot pasta water as needed to create a chunky sauce.
Arrange the dressed baby spinach on a large platter. Top the spinach with the tossed pasta, then add the roasted cherry tomatoes and sprinkle with crumbled goat cheese. Serve immediately.