Heat a skillet or grill pan over medium-high heat. Brush both sides of the sourdough slices lightly with 1 tsp extra-virgin olive oil (or spread 1 tsp butter on one side if using). Toast slices 1–2 minutes per side until golden brown and crisp with good grill marks. Alternatively, use a toaster and then rub one side with oil or spread butter.

Place toasted bread on a cutting board or plates. While still warm, set aside so avocado topping will adhere better.

Avocado mixture

Prepare avocado

Cut the avocado in half, remove the pit, and scoop the flesh into a medium bowl. Mash with a fork to your desired texture: mostly smooth with some small chunks for texture.

Add 1 tbsp fresh lemon juice immediately to the mashed avocado to preserve color and add brightness.

Season the avocado with 1 tsp sea salt, 1 tsp freshly ground black pepper and 1 tsp red pepper flakes. Taste and adjust: add up to 1/4 tsp more salt or additional lemon juice if needed. Mix until evenly combined.

Assembly & toppings

Spread avocado

Divide the avocado mixture evenly between the two toasted slices, spreading it to the edges with the back of a spoon or an offset spatula. Leave a small border if you prefer less mess.

Add toppings (optional)

Scatter halved cherry tomatoes and thin radish slices over the avocado. Add microgreens or baby arugula for freshness, and sprinkle 2 tbsp crumbled feta if using. Finish with 1/2 tsp everything bagel seasoning distributed across both slices and a light 1/2 tsp drizzle of olive oil.

If serving immediately, garnish with an extra crack of black pepper and a small pinch of flaky sea salt to taste. Serve immediately while toast is crisp.