Cream the butter and sugars. In a large bowl, beat the softened butter with the brown and granulated sugars until light and fluffy, about 2–3 minutes. Use a hand mixer or stand mixer on medium speed.

Add eggs and vanilla. Beat in the eggs one at a time, then mix in the vanilla. Scrape down the bowl to make sure everything is well combined.

Whisk dry ingredients. In a separate bowl, whisk together flour, baking soda, baking powder, and salt.

Combine wet and dry. Add the dry ingredients to the butter mixture on low speed until just combined.Do not overmix. Fold in the chocolate chips if using.

Chill the dough. Cover the bowl and refrigerate for 30–60 minutes. Chilled dough is easier to handle and bakes thicker, which helps contain the filling.

Preheat and prep. Heat the oven to 350°F (175°C).Line two baking sheets with parchment paper or silicone mats.

Portion and stuff. Scoop about 2 tablespoons of dough (roughly 40–45 g). Flatten it into a disk. Place a frozen mini creme egg in the center and wrap the dough around it, sealing well so no candy is exposed.Roll into a smooth ball. Repeat with remaining dough and eggs.

Space and bake. Arrange dough balls on the baking sheets, leaving at least 2 inches between cookies. Bake for 10–12 minutes, until the edges are set and lightly golden, but the centers still look slightly underbaked.

Finish and cool. If you like, sprinkle a tiny pinch of flaky sea salt on each cookie right out of the oven.Let cookies cool on the sheet for 10 minutes before moving to a rack. Serve warm for the gooey center.