Place the marshmallows in a large microwave-safe bowl and heat for 25-30 seconds. Stir well, and repeat heating as needed.
Add the melted coconut oil and vanilla extract to the marshmallows and stir well to incorporate.
Add the rice cereal cup at a time, gently folding it into the marshmallow mixture, until all of the cereal is incorporated. We ended up using our hands and mixing it up that way, it took a lot of effort but much more fun!
Scoop heaping 1/4 cup portions of the rice krispie treats into the prepared muffin tray.
Wet your hands and press the rice krispies into a cup or tart-shape. Wetting your hands is key! It makes it much less sticky
Place in the fridge for 2 hours or overnight to set.
When the nests have had a chance to set and harden, pop them out of the muffin tray using a butter knife and fill with treats, we used the cadbury mini eggs but feel free to deviate!