Make the pesto by placing all of the ingredients into a powerful food processor and blending until a thick, green pesto forms. once blended, place the pesto into a pan over a medium heat.
add the chopped spinach and frozen peas and heat until the spinach has wilted. once wilted, turn off the heat and put to one side until needed.
make the white sauce by placing the tapioca flour, lemon juice, nutritional yeast, mustard, almond milk and a pinch of salt into a pan over a medium heat, and cook until the mixture begins to bubble, continuously whisking to ensure the mixture stays smooth and doesn’t form any lumps.
continue whisking until the mixture becomes thick and elastic-like. at this point, remove from the heat and continue whisking to ensure it remains smooth – adding a dash more almond milk if it becomes too thick.
once ready to assemble the lasagne; spoon one third of the pesto mixture onto the bottom of a baking dish. top with one quarter of the white sauce and cover with one layer of lasagne sheets. repeat this process twice more, with pesto sauce, white sauce, lasagne sheets, until you have finished all of the pesto and you are left with lasagne sheets on top. top with the last of the white sauce.
sprinkle with nutritional yeast and place in the oven to cook for 35-40 minutes until bubbling and golden on top.