Preheat the oven to 175°C (350°F). Lightly grease a 10–11 inch (25–28 cm) round pizza pan or line it with parchment paper leaving a slight overhang for lifting.

Melt butter and combine sugars

In a heatproof bowl over a saucepan of simmering water or in short bursts in the microwave, melt the butter until fully liquid. Stir in the granulated sugar and light brown sugar until mostly dissolved and slightly glossy.

Add eggs and vanilla

Allow the butter-sugar mixture to cool for 1–2 minutes, then whisk in the eggs one at a time until smooth and homogenous. Stir in the vanilla extract.

Combine dry ingredients

In a separate bowl, sift or whisk together the all-purpose flour, unsweetened cocoa powder, fine salt and baking powder until evenly distributed.

Mix batter

Fold the dry ingredients into the wet mixture in two additions, mixing just until combined and no streaks remain. Fold in the semi-sweet chocolate chips.

Shape and bake

Spread the batter evenly into the prepared pizza pan, smoothing the top with a spatula so it reaches the edges and is roughly pizza-crust thickness (about 1–1.5 cm thick). Bake in the preheated oven for 18–22 minutes. The center should be set but slightly fudgy — a toothpick inserted near the center will come out with a few moist crumbs.

Cool

Remove the brownie crust from the oven and let it cool in the pan for 15 minutes. Then carefully lift the parchment or invert onto a rack to cool another 20–30 minutes until warm or near-room temperature (cooling prevents toppings from melting excessively).

Toppings (pizza-style)

Prepare toppings

While the brownie crust cools, hull and chop strawberries, measure out marshmallows, mini chips and cookie crumbs. Warm caramel sauce slightly if it is stiff so it is easily drizzleable.

Assemble

Place the cooled brownie crust on a serving board or keep it in the pan. Starting from the center, arrange chopped strawberries and scatter mini marshmallows and mini chocolate chips evenly across the top. Sprinkle the crushed Oreo or cookie crumbs for texture. Drizzle caramel sauce over the entire surface in a spiral or zigzag pattern. If you like a salty-sweet contrast, sprinkle sea salt flakes lightly across the top.

Toast marshmallows (optional)

If you prefer toasted marshmallows, place the assembled pizza (or just the marshmallow-topped sections) under a hot broiler for 20–45 seconds, watching closely until marshmallows are golden and puffed, then remove immediately. Alternatively use a kitchen torch to toast individual marshmallows.

Finish

Dust lightly with powdered sugar if using and scatter fresh mint leaves for color. Serve immediately with scoops of vanilla ice cream on the side or on top of slices.

Finishing (optional)

Slice the brownie pizza into 8 wedges. Serve warm with a scoop (approx. 60 ml) of vanilla ice cream on each slice. For an extra touch, finish each slice with a small pinch of sea salt flakes to enhance the chocolate and caramel flavors.