Reese’s Peanut Butter Cups have always been made with real milk chocolate or dark chocolate and peanut butter. But a small portion of Hershey’s and Reese’s products, like mini Easter eggs, are now made with a coating that contains less chocolate.

Hershey said that in 2027, it will shift those products to “their classic milk chocolate and dark chocolate recipes.”

The Hershey, Pennsylvania-based company said it will also be making other changes to its sweets portfolio next year, including transitioning to natural colors and enhancing Kit-Kat’s recipe to make it creamier. The company said it plans to increase its research and development funding by 25% next year.

“Hershey is committed to making products consumers love and that means continually reviewing our recipes to meet evolving tastes and preferences,” the company said in a statement.

Brad Reese, the grandson of the inventor of Reese’s Peanut Butter Cups, ignited the controversy in a public letter he sent to Hershey’s corporate brand manager on Valentine’s Day.

“How does The Hershey Co. continue to position Reese’s as its flagship brand, a symbol of trust, quality and leadership, while quietly replacing the very ingredients (Milk Chocolate + Peanut Butter) that built Reese’s trust in the first place?” Reese wrote in the letter, which he posted on his LinkedIn profile.

Hershey acknowledged some recipe changes but said it was trying to meet consumer demand for innovation. High cocoa prices also have led Hershey and other manufacturers to experiment with using less chocolate in recent years.

The Associated Press left a message with Brad Reese on Wednesday seeking comment.

Brad Reese is the grandson of H.B. Reese, who spent two years at Hershey before forming his own candy company in 1919. H.B. Reese invented Reese’s Peanut Butter Cups in 1928; his six sons eventually sold his company to Hershey in 1963.