This recipe comes from Anna Lise Kvan, of Paris’ Holy Belly Café. She rightly calls it a labor of love since it requires patience and a little elbow grease—it’s important to keep stirring to make sure that the rhubarb and onions are caramelizing but not sticking to the bottom of the pan. The final result is worth the effort. Make a big batch, so you can keep it in the fridge for up to two weeks. She suggests pairing this with roasted pork cutlets or tenderloin, or spreading it on turkey, chicken, or ham sandwiches. We also like adding it to grilled cheese sandwiches.