Heat oven 300'F. Toss tomaotes with garlic and olive oil in a oven safe baking dish. Bake for 40-50 minutes or until tomates have softened.
Heat large saute pan over medium heat. Add avocado oil and onion. Cook for 15-20 minutes until onions begin to soften and carmelize. Add green beans and deglaze the pan with marsala wine. Season with salt and pepper about 1 tsp each. Increase heat to high and toss green beans and onions with balsalmic vinegar, cook 2-3 minutes. Remove from heat.
Toss tomatoes into green bean mixture. Season with additional salt and pepper if needed. Top with fresh horseradish and parsley.