Grab a large, heavy-bottomed pot. Toss in your prepared figs (stems removed, cut into ½-inch pieces), the lovely orange and lemon zest, the sugar, and that little pinch of salt. Give it all a good stir to combine.
Just let that mixture sit there for about 30 minutes. You'll notice the sugar starting to work its magic, drawing out the delicious juices from the figs. This step is called maceration, and it helps create a beautiful syrup before you even start cooking.
After the rest, place your pot over medium heat. Bring the mixture to a gentle boil. You'll want to stir constantly during this part to make sure all that sugar dissolves completely.
Once it's bubbling gently, reduce the heat to low and let it simmer. Stir frequently to prevent sticking. The jam will gradually thicken as the liquid evaporates and the natural pectin in the figs does its job. This can take anywhere from 40 to 60 minutes, or even a bit longer depending on your stove and pot. Keep an eye on it – you're looking for it to reach your desired consistency. It will thicken more as it cools, so keep that in mind!
When your jam looks just right – perhaps coating the back of a spoon nicely – carefully remove the pot from the heat. Now is the time to stir in the Grand Marnier. Give it a good swirl to incorporate the lovely orange liqueur flavor.
Finally, it's time to jar your liquid gold! Carefully ladle the hot jam into sterilized jars, leaving about ½ inch of space at the top (called headspace). This is important if you plan on canning.
Wipe any jam off the rims with a clean damp cloth (this helps ensure a good seal), place the lids and rings on.
Then you have two options: you can process them in a boiling water bath for 10 minutes (remember to adjust time for altitude if needed – check a reliable canning guide!) for shelf-stable storage, or if you plan to use it right away, just pop the jars into the refrigerator once they've cooled a bit.