Scrub and trim the vegetables. I like to peel them for this recipe (it helps make the mash creamier) but you can leave the skin on if desired. Slice the carrots and dice the swede/rutabaga into cubes.
Place the veggies in a pot and add just enough water to cover them. Bring to a boil, cover, and let them cook for ~10 minutes or until tender. While the veggies are cooking, melt the butter in a small skillet and add the herbs and lemon juice. Remove from heat.
Drain the water and transfer the carrots and swede to a high-powered blender. Add the herbed butter and blend until smooth, ~1 minute. You may need to stop the blender and push the mash down the sides a few times. Add a dash of liquid (water, broth, or milk) to promote blending if needed. Alternatively, you can use a potato masher to mash the veggies in their pot.
Serve warm with another pat of butter, salt, pepper, and more herbs as desired. Enjoy!
Notes
Store leftovers in an airtight container in the fridge for up to 5 days or the freezer for up to 3 months (thaw in the fridge). Reheat in the microwave or in a small saucepan over low heat on the stove.
You can add or substitute different herbs depending on your taste preference.