This beautiful tart is a perfect quick treat to make for a party, for appetizers, or for a brunch. The rich buttery flavor of the puff pastry melds with the Yukon Gold potatoes, nutty Gruyere cheese and fresh asparagus.
1 sheet of thawed puff pastry
2 Yukon gold potatoes
1/2 bunch of asparagus, washed and trimmed
1 cup grated Gruyere cheese
2 Tbl sour cream
1 Tbl mustard (I used Sierra Nevada Porter mustard but Dijon or grainy mustard is also perfect)
Salt and pepper
1 tsp. fresh thyme leaves
Preheat the oven to 400F.
Simmer the potatoes whole in salted water until they are just tender when pierced, mine cooked for 30 minutes. Let cool, peel and slice thinly. Sprinkle with Kosher salt.
On a cookie tray, gently roll out the puff pastry a little bit into an even square. With a very sharp knife trim off an inch around each side of the pastry. Using cold water and your fingers, wet the edges of the pastry and lay on the cut pieces of pastry to form a square frame over the whole pastry piece. Press gently with your fingers.
Using the back of a spoon, spread the mustard inside the pastry square, then dollop on the sour cream and smoothly to spread evenly over the mustard coated pastry.
Add the potatoes in one layer leaving space between each slice. Sprinkle most of the cheese over the potatoes. Lay the asparagus spears over the potatoes and cheese, and then gently sprinkle them with more cheese, salt and pepper, and the leaves of thyme.
Bake at 400 F for 30 minutes, until the pastry is crisp and golden brown around the edges. Let cool on the baking tray and then transfer to a serving platter. Cut into pieces with a sharp knife and eat with a glass of cold Champagne.