Whisk together four egg yolks, sugar, a pinch of salt, and a little lemon juice in a small saucepan. Stir in the condensed milk. Warm gently over low heat, stirring often, until the sugar melts and the yolks are fully blended. Take off the heat and let it cool.
Once cooled, transfer the custard to a blender or food processor. Add the spruce tips and blend on high for about 2 minutes until everything is smooth and well combined.
Pour the spruce base into a container, cover, and chill in the fridge for at least 24 hours. This helps the flavors develop and the color deepen. The longer it sits, the better it gets.
Strain out any remaining spruce bits using clean gauze, cheesecloth, or a fine sieve. The mixture will be much thicker now and a nice foresty green.
In a separate bowl, whip the cream until soft peaks form (sweeten if you like). Gently fold in the spruce custard, being careful not to deflate the cream. Transfer into a loaf tin or shallow container, level the top, cover with foil, and freeze.
To keep the texture creamy, whisk the ice cream gently every hour using a hand mixer. Do this 3–4 times until fully frozen, which usually takes about 4 to 6 hours.
Add a dusting of spruce tip sugar on top, drizzle with spruce tip syrup or melted chocolate and serve. Enjoy!