Begin by placing 1/2 gallon of water in a large pot and bringing it to a boil. The water should be bubbling vigorously, signaling it's ready for the next step.
Once boiling, add 4/5 cup of chicken stock, 1 chopped onion, 1 chopped carrot, and 12 oz of chicken breast. Season everything with a little salt and pepper. Allow this mixture to simmer for 20 minutes, letting the flavors meld beautifully.
While the chicken cooks, prepare your asparagus. If using fresh, boil it in a separate pot of salted water for about 15 to 20 minutes until it's tender. Once cooked, remove it and cut it into small chunks.
When the chicken is done, carefully transfer it to a dish to cool. Once cool enough to handle, dice the chicken into small pieces. You want them bite-sized for your tartlets.
Next, strain the chicken soup and reserve the liquid for later use. Discard the cooked vegetables unless you wish to chop them finely and add to the tartlets.
In a saucepan, melt 1 1/2 oz of butter. Once melted, stir in 5 tbsp of all-purpose flour to create a roux, cooking it until it’s golden and fragrant. Be sure to stir constantly to prevent burning.
Slowly add 4/5 cup of milk to the roux, whisking continuously to avoid lumps. Gradually incorporate 4/5 cup of the reserved chicken soup, ensuring everything is well combined.
Adjust the seasoning by tasting and adding more salt or pepper as necessary. Allow the mixture to cook and thicken for about 10 minutes, stirring regularly.
Once thick, fold in the diced chicken and asparagus pieces, gently mixing to ensure they are fully coated in the creamy sauce. Heat everything through until warm.
Warm the tartlet cups according to package instructions. When ready, fill them generously with the chicken and asparagus mixture, ensuring they’re loaded with flavor.
For the finishing touch, sprinkle a pinch of chopped parsley or dill over the top for a pop of color and freshness. Serve them up and enjoy every crispy, creamy bite!
