fresh green beans, rinsed, trimmed and halved
(30g) unsalted butter
mushrooms, sliced into halves or quarters*
ground black pepper
garlic, minced (minced roasted garlic is great here)
(15g) all-purpose flour
(180ml) chicken or vegetable broth
1/4 cups (300ml) half-and-half*
Preheat the oven to 475°F (246°C). Line a large baking sheet with parchment paper or a silicone baking mat. Set aside.
For the onions: (while the onions bake, you can blanch the green beans– step 4.) Thinly slice the onion. Pour flour in one small bowl, Panko + salt + pepper into a medium bowl, and whisk the egg and milk together in another small bowl. To bread the onion slices, you’ll want to use one hand for dry and one hand for wet. It helps things move a little quicker and easier. First, dip a few slices into the flour. Then into the egg mixture. And finally, give them a nice dunk into the Panko and coat them well. Place onto baking sheet. Repeat with the rest of the onions. Bake onions until golden brown, about 25 minutes. Flip them twice during this time. Set them aside.
Reduce oven to 400°F (204°C).
Bring a gallon of water and 1 Tablespoon of salt to a boil in a large saucepan. Add the beans and blanch for 5 minutes. Drain and immediately place into a large bowl filled with ice water to stop the cooking process. Drain again and set aside.
For the casserole: Over medium-high heat, melt the butter in a large 10 – 12 inch ovenproof skillet. Add the mushrooms, 1 teaspoon salt, and the pepper. Cook, stirring occasionally, until the mushrooms begin to give off some of their moisture– about 5 minutes. Add the garlic, stir, and cook for another 2 minutes. Sprinkle the flour on top and stir until combined. The flour will soak up all the moisture. Add the chicken broth and simmer for 3 minutes. Decrease the heat to medium-low and add the half-and-half. Stirring occasionally, cook until the mixture is thick– about 10 minutes or maybe more if you prefer a thicker sauce.
Remove from the heat and add 1/4 of the onions and all of the green beans. Give it a nice stir, combining the sauce and beans. Top with remaining onions and bake until bubbly, about 10-15 minutes. Remove from the oven and enjoy! Leftovers keep well in an airtight container in the refrigerator for up to 4 days. Reheat as desired.
Make Ahead & Freezing Instructions: Prepare everything as directed, except turn oven off after the onions are done, do not heat to 400°F (204°C). After the sauce is finished and the casserole is assembled, set aside and allow to cool. Cover tightly either in the skillet or carefully transfer to another dish. Refrigerate overnight. The next day, bake for 15-20 minutes at 400°F (204°C) until bubbly. You can also prepare the casserole, including topping with onions, then freeze for up to 3 months before baking. Thaw in the refrigerator then bake as directed.
Onion Topping: If you’re not really into the baked “fried” onions, feel free to use a small or medium onion instead. Or leave it out completely and sprinkle the top of the casserole (before going into the oven) with 1/2 cup Panko breadcrumbs for crunch.
Panko Breadcrumbs: Panko is a Japanese style breadcrumb found in all major grocery stores or anywhere breadcrumbs are sold. It gives the onions a heartier crunch.
Mushrooms: Feel free to leave out the mushrooms or replace with thinly sliced bell pepper.
Half-and-Half: I tested this recipe with varying amounts of half-and-half– this amount does the trick. You can use heavy cream instead of the half-and-half for a richer sauce if you prefer. I do not recommend whole milk or buttermilk (or any other lower fat milks) instead. You want a thick, rich sauce.
Want to double the recipe to feed a larger crowd? It’s easy! Simply double the ingredients. Then in step 6, remove the skillet from heat then pour the bean mixture into a large 9×13 (or similar size) casserole dish. Top with onions, then bake until bubbly, around 20 minutes.
Adapted from Alton Brown— he likes to add fresh ground nutmeg, but I wasn’t really a fan. Feel free to add some though!
This will keep the pastry from puffing up too much during cooking. GreenBeanCasserole Tartlets transform the classic Thanksgiving side dish into a delicious finger food appetizer that is perfect for the holidays