Place a small plate in the freezer for testing set later. In a large wide saucepan, combine strawberries, sugar, lemon juice, lemon zest, and a pinch of salt. Stir to dissolve some of the sugar.

Use a potato masher to gently mash strawberries until juicy but still a bit chunky (or blend briefly for smoother jam).

Bring mixture to a lively boil over medium-high heat, stirring often. Reduce heat to medium and maintain a steady simmer, stirring frequently to prevent scorching.

Cook 25–30 minutes until thickened. If using a thermometer, aim for about 220°F. Skim any foam for a clearer set and brighter color.

Test for doneness: Dab a spoonful on the chilled plate, wait 60 seconds, then nudge it with your finger. If it wrinkles and holds its shape, the jam is set. If not, simmer 3–5 minutes more and retest.

Remove from heat. For fridge/freezer jam, let cool 5 minutes, then ladle into clean jars leaving about 1/4 inch headspace. Seal, cool to room temperature, and refrigerate up to 3 weeks or freeze up to 6 months.

For shelf-stable storage, ladle hot jam into sterilized jars, leaving 1/4 inch headspace. Wipe rims, apply lids and rings, and process in a boiling water bath for 10 minutes (adjust for altitude). Let cool and check seals before storing.