Uillinn Cheese and Caramelized Onion Tart

By AislePrompt Editorial · Published 2026-04-14 · Updated 2026-04-14

A flaky puff pastry crust filled with slow-simmered onions and nutty Uillinn cheese, finished with a golden egg wash. This Irish-inspired vegetarian recipe, ready in about 50 minutes, layers onion, butter, white wine into a dessert worth slowing down for — great for weekend baking, holiday tables, or any time you want a sweet payoff at the end of a meal. Each serving lands at about 320 calories and feeds 8, so it slots into a weekend bake or a special-occasion dessert tray. 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

• 1 large, thinly sliced onion
• 2 tbsp butter
• 1/4 cup white wine
• 1/4 tsp salt
• 1/4 tsp black pepper
• 2 cups, shredded Uillinn cheese
• 1 sheet, thawed puff pastry
• 1, beaten egg

The pan we’d use for this → Best Nonstick Cookware for 2026: Top 5 Skillet Picks + Buying Guide

Instructions

1. Step 1: Preheat oven to 375°F. In a skillet, melt 2 tbsp butter over medium heat.
2. Step 2: Add 1 large thinly sliced onion, 1/4 tsp salt, and 1/4 tsp black pepper. Cook uncovered for 25 minutes, stirring occasionally, until deeply golden and caramelized.
3. Step 3: Stir in 1/4 cup white wine and cook for 2 more minutes until wine evaporates.
4. Step 4: Roll out 1 sheet puff pastry on a floured surface to fit a 9-inch tart pan. Press into the pan and trim edges.
5. Step 5: Spread caramelized onions evenly over pastry, then sprinkle 2 cups shredded Uillinn cheese on top.
6. Step 6: Brush edges with 1 beaten egg, then bake for 20-25 minutes until pastry is golden and cheese is bubbly.