Convenience: Using frozen peppers and onions cuts down on prep time significantly, as there’s no need to wash, chop, or slice ...

Start the onions: Combine oil, anchovies and red pepper flakes in a skillet set ... salt. Pulse to mix. Add frozen butter and process until mixture is the texture of coarse meal, about 15 seconds.

Add the onion, season with salt and pepper ... the frozen spinach to the pan, along with 400 millilitres of the starchy pasta water. Increase the heat and cook the spinach and onion mix until ...