Preheat oven to 350°F. Coat a 1-quart baking dish or an 8-inch cast-iron skillet with cooking spray. Combine water, cashews and garlic in a large microwaveable bowl. Arrange cauliflower in even layer on top of the cashew mixture (do not stir). Cover lightly with plastic wrap. Microwave on High until the cauliflower and cashews are soft, about 7 minutes.

Carefully transfer all contents (including liquid) to a food processor. Process until smooth, scraping down sides as needed, about 1 minute. Add mayonnaise, nutritional yeast, miso, mustard, lemon juice, pepper and salt; process until fully combined. Add artichokes and spinach; pulse until just combined.

Transfer to the prepared baking dish or skillet; cover with foil. Bake for 20 minutes; uncover and continue baking until bubbly and just starting to brown along the edges, about 10 minutes more. (Alternatively, this can be served warm or at room temperature straight from the food processor.) Garnish with crushed red pepper, if desired. Serve with chips and/or crudités.