1. Line a jellyroll plan with parchment paper. Place sliced tomatoes on parchment in one layer (do not overlap). Bruch tomatoes with olive oil, then sprinkle with thyme and garlic powder. Bake at 375 for 45 minutes or until done.
2. While tomatoes are roasting, slice the onion. Heat the butter in a pan on medium-low, and cook the onions for about 30 minutes, or until golden brown.
3. While tomatoes are roasting and onion is cooking, fry bacon until crispy. Remove from pan, set aside on paper towels to cool and drain, then crumble.
4. Whisk eggs, cashew milk, salt, and pepper in a bowl.
5. Layer roasted tomatoes, cooked onions, and crumbled bacon in a 9-inch pie plate. Pour egg mixture over top. Bake at 350 for 30 minutes, or until the eggs are set. Remove from oven and let rest for 10 minutes. Serve with chives and sliced avocado.