When I’m really stuck for a quick supper, I turn to eggs! Not fried, poached, or scrambled, but to what the French (and the Irish) call a tart or a quiche. While many use the term interchangeably, the main difference, I’m told, is the amount of egg mixture that’s poured into the pastry base: a quiche uses more eggs, while a tart uses fewer eggs and generally more filling. This luscious onion-spinach tart is French in form, but all Irish in substance with the delicious addition of Tipperary-made Cashel Blue cheese. The recipe originally appeared in my Flavors of Ireland cookbook, adapted from one found at Ely Wine Bar in Dublin. For a really quick supper, substitute a prepared piecrust for the pastry. Follow the directions for pre-baking the crust for custard pies and quiches and then follow the directions for filling.

Caramelized Onion-Spinach-Blue Cheese Tart

Serves 6

Pastry

1 1/4 cups all-purpose flour

Pinch of salt

8 tablespoons unsalted butter, cut into small pieces

1 large egg yolk

2 tablespoons cold water

Filling

4 tablespoons olive oil

2 large red onions, thinly sliced

1 tablespoon fresh thyme leaves

1 cup baby spinach leaves

1 tablespoons brown sugar

2 tablespoons balsamic vinegar

1 cup crumbled Kerrygold Cashel Blue cheese

1/2 cup heavy (whipping) cream

1 (8 ounce) container sour cream

2 large eggs

Pinch of nutmeg

Salt and freshly ground pepper to taste

Thyme sprigs for garnish

1. Make pastry. Sift flour and salt into a food processor fitted. Add butter and pulse 8 to 10 times until mixture resembles fine breadcrumbs. With machine running, add egg yolk and just enough water to bring dough together.
2. Turn out onto lightly floured surface and form dough into a ball. Wrap in plastic and refrigerate for 1 hour.
3. Preheat oven to 400°F. On a lightly floured surface, roll out dough to a 12-inch round. Press into a 10-inch tart pan with removable bottom. Fold in excess dough to form thick edges. Prick bottom with a fork and refrigerate for about 15 minutes.
4. Cut a piece of foil or parchment to fit pan and top with pie weights or dried beans. Bake for 18 to 20 minutes, or until edges are lightly browned.
5. Remove weights and parchment and bake for 10–15 minutes more, or until bottom is browned. Remove from oven and let cool in the pan on a wire rack. Reduce heat to 350°F.
6. Make filling. In a large skillet over medium heat, heat olive oil. Add onions, thyme, and spinach and cook for 3 to 5 minutes, or until onions are soft but not browned. Add sugar and cook for 5 minutes. Add vinegar, stir, and remove from heat; let cool. Strain off excess liquid and spread onion-spinach mixture evenly over baked pastry. Sprinkle cheese over onions.
7. In a medium bowl, whisk together cream, sour cream, eggs, nutmeg, salt, and pepper. Pour over cheese and onions and bake for 35 to 40 minutes or until top is golden and filling is set. Remove from oven and let cool for 15 minutes before cutting into wedges. Garnish with thyme sprigs.