If you have a food processor, pulse the oats, protein powder and salt 3–4 times to combine and break the oats down slightly; otherwise whisk them together in a large bowl.
Warm the peanut butter and honey together in a microwave-safe bowl in 20–30 second bursts, stirring between bursts, until they’re glossy and easily pourable. Stir in the vanilla extract and almond milk until smooth.
Pour the warm peanut butter mixture over the dry ingredients. Stir with a sturdy spatula or wooden spoon until everything is evenly moistened and the mixture holds together when pressed. If it feels too dry, add 1 tablespoon more almond milk.
Fold in about three-quarters of the chopped Cadbury eggs, reserving the rest for finishing so you keep some larger candy bits for texture and appearance.
Cover the bowl and chill the mixture in the fridge for 15 minutes to firm up slightly—this makes shaping much easier and prevents the candy from melting into the batter.
Using a 1-tablespoon scoop (or wet hands), press and roll the mixture into 1-inch balls. As you form each ball, gently press a few reserved chopped Cadbury pieces into the outside of each bite so some candy shows on the surface.
Place the bites on a tray or plate in a single layer and refrigerate for 45 minutes to fully set. Once firm, transfer to an airtight container and keep chilled.