Line a 12-cup muffin pan with large paper liners and set aside.
In a large mixing bowl, combine the quick oats, ¾ cup peanut butter, and honey. Slightly warm the peanut butter and honey beforehand if needed for easier mixing.
Using a handheld mixer, blend until the oats are evenly coated and the mixture holds together.
Divide the oat mixture evenly among the prepared muffin liners, adding approximately ¼ cup per liner.
Using the back of a small measuring cup, firmly press the oat mixture into the bottom of each liner to form a compact, even base.
In a saucepan over medium heat, combine the chopped dark chocolate and the remaining ¼ cup peanut butter.
Stir continuously until the chocolate is completely melted and the mixture becomes smooth and creamy.
Transfer the melted chocolate mixture to a measuring cup, then carefully pour it over the oat bases, dividing it evenly among all 12 cups.
Use a spatula to gently spread the chocolate over each oat layer, ensuring the surface is evenly covered.
While the chocolate is still warm, sprinkle a small amount of flaky sea salt over each cup.
Place the muffin pan in the freezer for at least 30 minutes, or until the chocolate and oat layers are completely firm.
Once set, remove the cups from the muffin pan and serve directly from the freezer.