Drain the beans, reserve about 1/2 cup of the liquid (aka Aquafaba). Reserve for later.
Blend the silken tofu, or prepare the Cashew Cream. Reserve for later. In a large skillet (ideally with high walls), melt the vegan butter over medium heat.
Add in the minced garlic, Calabrian chiles or red chili flakes (if using). Stir and cook for 30 seconds. If garlic browns too quickly, lower the heat. Add in the Italian Seasoning and stir to combine, cooking for another 30 seconds.
Stir in the veggie broth, followed by the blended silken tofu. Start with 1/2 cup each, and reserve the rest for later to adjust the liquid levels to your preference.
Stir in dijon mustard, vegan parmesan, nutritional yeast, sun dried tomatoes and chopped spinach. Cook for about 2 - 3 minutes or until spinach has wilted and shrunken a bit.
If the mixture feels too thick, add some more broth / silken tofu to loosen it up.
Next add in the drained beans and gently stir (butter beans are delicate) to combine.
Add more broth or silken tofu if necessary. I like to add in a splash of the reserved aquafaba as this makes the sauce more creamy and emulsified.
Taste and adjust for seasoning to your preference and add any more liquid as needed. The sauce will thicken up as it cools as well, so keep that in mind!
Enjoy with some crusty bread, or over some rice or even pasta!
Store leftovers in the fridge and enjoy within 3 days. Gently reheat on the stovetop or microwave. You may need to add a little water / broth etc to loosen it up!