Adapted to reduce oil from Eating Well.

Ingredients
1/2 cup halved and very thinly sliced red onion
1 large lemon
1 Tbsp maple syrup (or other liquid sweetener)
1/2 tsp kosher salt (optional)
1/4 tsp freshly ground black pepper
3 small organic red or pink grapefruit
1 large ripe avocado
1/3 cup fresh pomegranate seeds
4 large fresh basil leaves
8 small leaves Boston lettuce

1. Place onion in a small bowl of cold water to soak. Set aside.
2. Finely grate 1 tsp zest and squeeze 2 Tbsp juice from lemon. Whisk the zest and juice, maple syrup, salt (if using), and pepper in a large bowl.
3. Peel grapefruit with a sharp knife, removing all peel and white pith. Working over a medium bowl, cut the segments from the surrounding membranes and let the drop into the bowl. Squeeze the peels and membranes over the bowl to extract all juice before discarding them. Halve, peel, and pit avocado. Cut lengthwise into 1/4-inch-thick slices, then cut the slices in half. Gently stir the avocado and pomegranate seeds into the grapefruit mixture.
4. Finely slice basil and drain the onion; gently stir into the grapefruit mixture. Arrange lettuce leaves on 4 salad plates. Top with the grapefruit mixture and serve immediately.