Spinach French Onion Cob Dip with Caramelized Onions

By AislePrompt Editorial · Published 2026-06-22 · Updated 2026-06-22

A luscious dip combining tender spinach and deeply caramelized onions, baked on a fresh cob loaf for a perfect party appetizer. This Australian-inspired snack recipe, ready in about 75 minutes, blends unsalted butter, yellow onions, fresh spinach into a versatile sauce that lifts everything from grain bowls and roasted vegetables to grilled proteins — a small-batch staple worth keeping in the fridge. Each serving lands at about 280 calories and feeds 8, so a small batch covers several meals across the week without taking over the fridge. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart. Nutrition values are approximate, calculated from USDA FoodData Central (fdc.nal.usda.gov) — verify against ingredient labels for any health-driven dietary plan.

Ingredients

• 2 tbsp unsalted butter
• 3 medium, thinly sliced yellow onions
• 6 cups, roughly chopped fresh spinach
• 8 oz, softened cream cheese
• 1/2 cup sour cream
• 1 cup grated Swiss cheese
• 1/2 cup grated Parmesan cheese
• 3, minced garlic cloves
• 1 tsp salt
• 1/2 tsp black pepper
• 1 large (about 12 oz) fresh cob loaf

The sheet pan we’d roast this on → Best Sheet Pans in 2026: Top Picks + Buying Guide

Instructions

1. Step 1: Heat 2 tbsp unsalted butter in a large skillet over medium-low heat. Add 3 thinly sliced yellow onions and cook, stirring occasionally, for 30-35 minutes until the onions are deep golden brown and caramelized.
2. Step 2: Add 3 minced garlic cloves and cook for 1 minute until fragrant. Stir in 6 cups roughly chopped fresh spinach and cook for 3-4 minutes until wilted and most moisture evaporates.
3. Step 3: Remove the skillet from heat and transfer the onion-spinach mixture to a mixing bowl. Add 8 oz softened cream cheese, 1/2 cup sour cream, 1 cup grated Swiss cheese, 1/2 cup grated Parmesan cheese, 1 tsp salt, and 1/2 tsp black pepper. Mix well until fully combined.
4. Step 4: Preheat oven to 350°F (175°C). Cut the top off the fresh cob loaf and hollow out the inside, leaving about a 1-inch thick shell.
5. Step 5: Fill the hollowed cob loaf with the spinach and onion dip mixture, pressing it down gently to fill all spaces.
6. Step 6: Place the filled cob loaf on a baking sheet and bake for 20 minutes until the cheese is melted and the dip is warmed through. Serve immediately.