The metal lids are heatproof ... on the sheet pan without the support of the canning lid. With the Mason jar lid muffin hack, you can easily bake your muffins without the need for a special ...

Loosely screw two-part metal lids onto the jar, but don’t tighten them. Put the jars on the steamer rack and put the lid on the pot ... in the oven right in a mason jar. But I’m just not ...