1. Prepare the Crust:

1. Preheat oven to 400°F (200°C). Line two baking sheets with parchment paper.
2. Toss eggplant, bell peppers, zucchini, and yellow squash with 3 tablespoons olive oil, salt, and pepper. Arrange in a single layer on the baking sheets. Roast for 20-25 minutes until tender and lightly charred, flipping halfway. Let cool slightly.
3. While vegetables cool, heat remaining 1 tablespoon olive oil in a small skillet over medium heat. Add walnuts and toast for 2-3 minutes until fragrant. Drizzle with honey, stir to coat, and cook for 1 more minute. Remove from heat and let cool.
4. In a small bowl, combine goat cheese with thyme, rosemary, and a pinch of black pepper until smooth.
5. Line a 9×5 inch loaf pan with plastic wrap, leaving overhang. Begin layering: start with a layer of roasted eggplant slices, slightly overlapping. Spread a thin layer of goat cheese mixture, then sprinkle some cranberries and honeyed walnuts. Repeat layers with zucchini, yellow squash, bell peppers, cheese, cranberries, and walnuts until all ingredients are used, ending with a layer of eggplant.
6. Fold the plastic wrap over the top to cover. Place a heavy dish or weights on top to press the terrine. Refrigerate for at least 4 hours or overnight.
7. To serve, unfold the plastic wrap, invert the terrine onto a serving platter, and carefully remove the plastic. Slice into 1-inch thick pieces, drizzle with balsamic glaze if desired, and serve chilled or at room temperature.