This is a lovely thing - sweet, bitter, tart & flowery all at once.
Lola's makes it - $8 - worth it.
Lola makes some really good jellies, marmelades and jams. However, the hand-made batches are small, so call first as they might sell out (link below). This is one of the best I've had of some very fine preserves.
Maggies in El Cerrito on San Pablo near Home Depot also sells Lola's baked goods and products. Doing my best to keep the place going (it's my nabe). I bought the bergamot marmelade there ... really great. I've been using it in yogurt and oatmeal (and a couple of guilty pleasure spoonfuls straight from the jar).
A note about Maggies, not all of the pastries and sandwiches are from Lola's. Be sure to ask.
Lola's bergamot marmalade is up there with June Taylor's bing cherry jam as one of the best preserves I have ever tasted.