Step 1

Place the strawberries, sugar, lemon juice and lemon zest in a large, heavy bottomed pot. I like to use a dutch oven, because it is wide, big and very sturdy.

Step 2

Since the berries are frozen, keep stirring everything until the sugar starts to dissolve and the berries start to melt. Soon, the sugar, lemon juice and lemon zest will be evenly distributed and coating the berries. Keep the pot covered until the berry mixture comes to a boil.

Step 3

Uncover, reduce the heat to low and keep simmering the jam for 35-45 minutes. Skim the foam off the top while the berries are cooking. If you’re using frozen berries, it will take longer to bring the jam to a boil and take a little bit longer to reach the right consistency, since the berries are frozen and will have more liquid than fresh berries. It will take longer for the extra liquid to evaporate. If you’re using a pot that isn’t wide, it will also take longer, since the smaller the surface area, the slower the evaporation. The jam is finished cooking when it has thickened and reached 215-220 degrees Fahrenheit. A simple test you can use if you don’t want to use a thermometer is the cold plate test. Chill a plate in the freezer before you start making jam. When the jam seems to have reached the proper consistency, place a dollop of jam on the plate and let it stand for a minute of two. It should start to gel and shouldn’t be too runny. If you run your finger through the center, it shouldn’t run back together.

Step 4

When the jam is done cooking, crush the berries with the back of a spoon, a potato masher or an immersion blender. It should be really easy to do it, since the berries are really soft at this point. You can make it as chunky or smooth as you like.

Step 5

Fill sterilized jars with the jam and close with sterilized lids. Store at room temperature up to a year for best results. Refrigerate after opening.