Cook pasta shells following packaging directions and preheat oven to 375°.
To make the filling, in a food processor, blend 1 cup of cauliflower with cashews, almonds, almond milk, vegetable broth, salt and pepper, blending until thickened. Add in spinach and pulse to incorporate. Set aside.
To make the topping, heat 3 tablespoons of olive oil in a large sauté pan over medium-high heat, add the cauliflower and sauté for 5 to 6 minutes, until the florets are tender. Once cauliflower is cooked, add capers and toss. Turn off the heat, then add lemon zest, crushed red pepper, panko bread crumbs and parsley. Toss to combine, then fill each shell with the filling.