Potato Kugel w/Caramelized Onions

Ingredients

• 1-1/2 pounds sweet potatoes/yams
• 1-1/2 pounds Yukon Gold potatoes
• 4 tbsp. olive oil
• 4 onions, chopped
• 1 tsp. chopped thyme
• 1 tbsp. sugar
• 4 eggs, beaten