Secure and lock the Instant Pot lid in place, ensure the venting valve is sealed, select the MANUAL setting, and cook on HIGH pressure for exactly 7 minutes.

Once the cooking cycle completes and the timer chimes, immediately perform a Quick Release to rapidly vent the steam, then carefully open the lid once the pin drops.

Carefully lift the steamer basket out and transfer the tender potatoes and parsnips into a large mixing bowl, then evenly sprinkle the 1 tsp. (0. 2 oz / 6g) of sea salt and 1 tsp. (0. 1 oz / 2g) of ground black pepper over the top.

Using a potato masher or an electric hand mixer on a low speed, slowly drizzle in the 5 tbsp. (2. 5 fl oz / 75g / 2.65 oz) of half and half along with the 2 tbsp. (1 oz / 28g) of melted butter, blending continuously until the vegetables reach a beautifully smooth, creamy consistency, and serve immediately while warm.

Cut Uniformly: Ensure your potato and parsnip chunks are cut to roughly the same size before placing them in the Instant Pot. This guarantees they cook evenly and finish at the same time, preventing hard lumps in your final mash.

Warm Your Dairy: Before blending the half and half and melted butter into the vegetables, make sure they are at least room temperature or slightly warmed. Cold dairy can cool down the potatoes quickly and make them harder to mix, which can lead to a gummy texture.

Remove Woody Cores: Larger parsnips often have a thick, woody core in the center that doesn't soften well, even under pressure. If your parsnips are quite large, quarter them lengthwise and slice out the tough inner core before cubing them.