Cut off 1/2 inch (1.25 cm) from each end of the zucchinis, then cut each one in half lengthwise, and using a spoon, gently scoop out the pulp, making sure to leave a border at the ends, then season the insides with salt and place the zucchinis cut side down over paper towels

In the meantime, heat a large fry pan with a medium heat and add in the olive oil

After a couple of minutes, add in the chopped onion and mix continuously, after 2 to 3 minutes and the onions are slightly translucent, add in the sliced mushrooms and a dash of salt, mix together, and then mix every 1 to 2 minutes so everything evenly sautés

In the meantime, add the zucchini pulp into a fine sieve, and using a wooden spoon, push down to remove any of the excess water

Once the mushrooms are lightly browned, about 7 to 8 minutes, add in the zucchini pulp, continue to sauté for 3 to 4 minutes, then add in the chopped garlic, dried thyme, and season with salt & pepper, mix continuously for 1 minute, then add in the flour and mix continuously for 1 minute, then add in the milk at room temperature, and gently mix together for 3 to 4 minutes or until you get a thick and creamy sauce, then turn off the heat, add in 1/2 cup (60 grams) shredded cheese, and mix together until well mixed

After leaving the zucchinis for 15 minutes, pat the insides completely dry, then stuff each one with the creamy mushroom filling, and then add them over a baking tray lined with parchment paper and top off with the remaining 1/2 cup (60 grams) shredded cheese, making sure to evenly spread it around each stuffed zucchini

Add the baking tray into a preheated oven, 200°C - 400°F, for 20 minutes or until the cheese is melted and golden baked

Transfer the stuffed zucchinis into a serving dish and top off with chopped chives, enjoy!