Sweet and Golden Potato Gratin | Kowalski's Markets

Ingredients

• - Kowalski's Butter
• as needed for greasing the baking dish
• 3 tbsp. Kowalski's Extra Virgin Olive Oil
• divided
• 2 medium sweet onions
• sliced
• 1 tsp. minced garlic
• 1 ½ lbs. medium round Kowalski's Yukon Gold Potatoes
• unpeeled
• sliced ¼" thick
• 1 ½ lbs. orange sweet potatoes
• peeled
• 1 ½ tsp. kosher salt
• ¼ tsp. freshly ground Kowalski's Black Peppercorns
• 1 cup (4 oz.) grated Gruyère cheese
• 1 tbsp. snipped fresh thyme