Preheat your oven to 400°F and lightly grease a 9x13 inch baking dish. While the oven heats, prepare all your ingredients: finely dice the onion into 1/4-inch pieces, dice the celery, slice the mushrooms, mince the garlic, trim the asparagus and cut into 1-inch lengths, drain and rinse the chickpeas thoroughly, and measure out the broth, soymilk, flour, and all spices. Having everything ready before you start cooking will keep the process smooth and prevent overcooking any components.

Heat 2 tablespoons of vegetable broth in a large skillet over medium-high heat. Add the diced onion and cook for 2-3 minutes until it begins to soften and turn translucent. Add the celery, mushrooms, and garlic, then cook for another 2-3 minutes, stirring occasionally, until the mushrooms release their moisture and the garlic becomes fragrant. This builds a flavorful foundation by allowing the vegetables to caramelize slightly and release their natural umami.

Add the trimmed asparagus to the skillet along with 2 tablespoons of vegetable broth. Cover the pan and cook for 2-3 minutes until the asparagus becomes bright green and just beginning to soften—it will continue cooking in the oven, so you want it tender-crisp at this stage. Stir occasionally to ensure even cooking.

In a small bowl, whisk together the flour with a few tablespoons of the unsweetened soymilk to create a smooth slurry with no lumps. Pour this mixture into the skillet along with the remaining soymilk, 1 cup vegetable broth, nutritional yeast, dried thyme, and dried basil. Stir constantly over medium heat for 1-2 minutes until the sauce thickens slightly and coats the back of a spoon. I like to add the lemon juice and season with salt and pepper just before adding the chickpeas—this way the acid brightens the earthy flavors without being muted by the cream. Gently fold in the drained chickpeas, then simmer the entire mixture for 5 minutes, stirring occasionally, to allow all the flavors to meld together.

Pour the vegetable and chickpea filling from Step 4 into your prepared baking dish, spreading it evenly. In a small bowl, toss the shredded hash browns with the smoked paprika and 1 tablespoon of olive oil until well coated, then distribute the potatoes evenly over the top of the filling. I find that lightly pressing the potatoes down helps them cook more evenly and create a crispier top layer.

Place the assembled casserole in the preheated 400°F oven and bake for 25-45 minutes (time will vary based on your oven). The casserole is done when the filling is bubbling around the edges and the hash brown topping is golden brown and crispy. If the top isn't as brown as you'd like after 25 minutes but the filling is already bubbly, you can place the casserole under the broiler for 1-2 minutes to quickly brown the potato topping—watch it carefully to prevent burning.