Preheat your oven to 350° F. This ensures a perfectly baked tartlet. While the oven heats up, you can prepare your muffin tin. Lightly spray 6 cups in a muffin tin with olive oil spray to prevent sticking.
Prepare the asparagus. Snap off and discard the woody end of the asparagus. Cut the tip ends into 1 1/2-inch pieces and cut the remaining parts of the stalks into 1-inch pieces. This uniformity helps them cook evenly.
Next, heat a nonstick pan over medium-high heat. Lightly spray it with olive oil spray. Add the chopped asparagus and garlic, sautéing for about 2 minutes. You want the asparagus to turn bright green and begin to soften.
Now, stir in the lemon juice and 1 tablespoon of water. Reduce the heat to low, cover the pan, and cook for 1 minute more. This will help the asparagus become tender while maintaining its vibrant color.
Using a slotted spoon, remove the asparagus pieces to a plate, reserving the pan juices and garlic for the filling.
Prepare the phyllo sheets. Place one phyllo sheet on a clean work surface. Lightly spray it with oil, and then layer another phyllo sheet on top. Repeat this process with two more sheets, ensuring they are well-oiled.
Cut the stacked phyllo into 4-inch squares. Gently fit one square into each prepared muffin cup, creating a little shell for your filling.
Distribute the 1-inch pieces of cooked asparagus and crumbled feta cheese evenly among the muffin cups. This ensures each tartlet gets a good mix of ingredients.
In a bowl, whisk together the half and half, egg, dill, and reserved pan juices from the asparagus. This mixture will act as the custard in each tartlet.
Evenly divide the custard mixture among the phyllo shells—aiming for about 3 1/2 tablespoons in each. Top each cup with two asparagus tips for presentation.
Finally, bake the tartlets in your preheated oven for about 30 minutes or until the custard is set and the phyllo is golden. The aroma will be irresistible!
