Prepare the puffs according to package instructions.

Meanwhile, heat oil over medium heat in a small skillet and add mushrooms. Sauté for 3-4 minutes. Add spinach and cook for another 1-2 minutes or until spinach has wilted. Remove from heat and chop spinach into smaller pieces with kitchen scissors.

Separate egg whites and yolks into two separate bowls. Whip egg whites with an electric hand mixer until soft peaks form (about 1 minute). Beat egg yolks for 30 seconds, then add in the heavy cream, salt, and pepper and beat for another 30 seconds. Stir in cooked vegetables and Parmesan.

With a spatula, fold egg whites into egg yolk mixture.

Liberally spray 8 muffin cups with nonstick cooking spray. Smash puffs on the bottom and up the sides of each muffin cup to make a puff cup base for your souffle. Use 4-5 puffs for each muffin cup. Pour the egg mixture into the muffin cups (fill to about 3/4 full) and bake for about 15 minutes until tops are golden brown.

Remove from oven and allow to cool for 5 minutes, then gently run a knife around the edges of the ramekins and remove the spinach and egg soufflé cups. Sprinkle with chives and drizzle with truffle oil just before serving. Note: Lining each muffin tin with a strip of parchment paper (leaving a slight overhang) can help with sticking.

Remove from oven and allow to cool for 5 minutes, then gently run a knife around the edges of the ramekins and remove the souffle cups. Sprinkle with chives and drizzle with truffle oil just before serving. Note: Lining each muffin tin with a strip of parchment paper (leaving a slight overhang) can help with sticking.