Preheat the oven to 180 C / 350 F.: The warm dry heat of the oven creates Maillard browning on the topping and gently cooks the fruit, releasing fragrant, jammy aromas. You will notice a comforting, toasty scent once the oven reaches temperature. Preheating ensures even baking from the moment the dish goes in. A common mistake is not waiting for full preheat, which can lead to uneven rise and longer bake times; if your oven runs cool, allow a few extra minutes.
Peel the zucchini. Slice in half lengthways, scoop out the seeds using a teaspoon and cut into 4 mm thick moons. Add with the sliced peaches, sweetener, lemon juice and melted butter to your baking dish and toss to combine.: When you toss these ingredients together, the mixture will glisten from the melted butter and lemon juice, releasing a faint citrus perfume that brightens the fruit. The thin 4 mm slices of zucchini soften quickly and blend into the peach texture, so the filling becomes tender rather than fibrous. Tossing ensures every piece is coated, which helps the juices mingle and prevents dry pockets. Avoid slicing unevenly, as thick pieces may remain undercooked and upset the dish's texture.
Mix all ingredients for the crumble topping in a separate bowl using a fork until a thick batter. Press some together with your fingers to form nice big chunks so it's thicker than a crumble.: As you fork the almond flour , coconut flour , melted butter , baking powder, sweetener, vanilla, and salt together, the mixture should come together into a slightly sticky batter that can be pressed into clumps. You may feel it change from powdery to cohesive under your fork, and that tactile shift signals proper hydration. This technique encourages large, rustic lumps rather than a fine crumb, which gives the cobbler its signature texture. A frequent misstep is overmixing, which can produce a uniform dough instead of those desirable chunkier pieces.
Spoon the topping over the base. Sprinkle golden erythritol on top. Bake for around 40 - 45 minutes till the filling is soft and the topping crisp. Keep an eye on it from about 25 minutes. Once the topping is golden brown, loosely cover the cobbler with a sheet of tin foil so the top doesn't burn.: By shaping pieces with your fingers, you create irregular, substantial islands that bake to golden, crisp tops and tender interiors. The contrast between crunchy edges and soft centers is key, and the finger formed chunks encourage that. Expect a faint buttery aroma as the fat distributes. If you press too hard and compact the topping, it may bake dense rather than airy, so keep the chunks loose and varied.
Serve with yoghurt, whipped cream or keto ice cream.: During baking, steam from the fruit will bubble and give off a luscious, fruity scent while the topping browns and develops a toffee note from the erythritol. Look for bubbling edges and a set topping that is golden and crisp. Tent with foil once the top reaches the desired color to avoid overbrowning. A common oversight is leaving it uncovered the whole time and ending up with a top that is too dark before the filling has softened, so check in and tent when needed.
Serve with yoghurt, whipped cream or keto ice cream.: The warm cobbler pairs beautifully with a cool dollop that contrasts temperature and texture, and the creaminess mellows the concentrated fruit sweetness. You will notice a pleasing marriage of warm, jammy peaches under crisp, buttery topping when you serve it, and the chilled accompaniment adds a silky finish. Avoid placing very cold ice cream directly on an extremely hot cobbler for long periods, as rapid melting can turn the topping soggy; serve immediately for best texture.