Wash and dry the cherries, remove the pits. Put the berries in a bowl and drizzle with cognac. Leave for 1 hour.
Make syrup from sugar and water. Add cherries to boiling syrup, boil for 1 minute. and take it off the fire. Leave for 24 hours.
Put the jam on the fire, bring to a boil, add the lemon sliced \u200b\u200band cook for 5 minutes. Leave again for 24 hours.
Put the jam back on the fire and boil for 15 minutes. Pour into sterilized jars and roll up. Wrap up for 24 hours.