Berkshire Hathaway-owned (BRK-B, BRK-A) See's Candies, the 100-year-old maker and seller of chocolates, lollipops, toffee, and Warren Buffett's favorite treat — peanut brittle — had its best quarter ever at the start of 2021, according to CEO Pat Egan.

"We're fully back, I believe. We've had our best January ever, our best February ever, we just completed our best first quarter ever," Egan told Yahoo Finance ahead of the 2021 Berkshire Hathaway Annual Meeting, streaming exclusively on Yahoo Finance.

Egan, who took the helm at See's Candies in the spring of 2019 and is the third CEO in the company's history, described the past year as "the longest decade" of his life as the famed candy purveyor navigated the COVID-19 crisis.

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As the coronavirus pandemic hit the U.S. last March, See's closed all of its 245 stores in a matter of days and soon after closed its e-commerce fulfillment center in Southern California.

"So from that point forward what we did was we just said, 'We're not going to reopen stores or reopen our plants until we can create a safe operating environment for all of our employees.' That took a while, and by the time we restored at the end of the summer, we saw customers coming back in. But for that period of time, it was pretty rough," Egan added.

Amid pandemic lockdowns and stay-at-home orders, See's Candies' e-commerce business grew about 70% in total packages shipped last year. What's more, even with store reopenings, online sales have remained robust.

"[What] you might expect would be that when the stores reopened [e-commerce] would trail off a little bit. It hasn't. Our first quarter, we were up almost 160% over the first quarter of last year."

Egan noted that the traffic back in stores had been gradually, but the company is "almost back to 100%."

"But our e-commerce, which has more than doubled, has actually stayed at that level, and we're just fine with it not coming back to Earth. It creates some different operational challenges, but we've definitely expanded our customer base," Egan added.

Julia La Roche is a correspondent for Yahoo Finance. Follow her on Twitter.

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