Step-1Toast fennel seeds, red pepper, and bay leaves in a skillet over medium for 2 minutes, stirring often, until fragrant. Cool 10 minutes. Transfer to a spice mill (or mortar and pestle); finely grind. Set aside.
Step-2Place porcini mushrooms and 1 1/2 cups warm water in a bowl; let stand 15 minutes. Drain, reserving 1/2 cup soaking liquid. Finely chop mushrooms; set aside.
Step-3Pulse shiitake mushrooms, onion, carrots, and celery in a food processor until finely chopped, 10 to 12 times.
Step-4Heat oil in a large Dutch oven over medium. Add tempeh; cook 5 minutes or until golden. Add shiitake mixture, salt, and pepper; cook 10 minutes or until softened. Add garlic, ground spices, and chopped porcinis; cook 5 minutes or until mixed well.
Step-5Pulse tomatoes in a food processor until finely chopped, 8 to 10 times.
Step-6Stir chopped tomatoes, milk, wine, cheese rind, oregano, basil, sugar, and reserved 1/2 cup porcini soaking liquid into tempeh mixture in Dutch oven. Reduce heat to medium-low, and simmer, partially covered, stirring occasionally, about 1 hour. Remove cheese rind; stir in grated cheese.
Step-7Cook spaghetti per package directions. Toss with butter to coat; serve with Bolognese; garnish with fresh basil, if desired.