Step 1

Arrange a rack in the middle of the oven and heat the oven to 325°F.

Step 2

Coarsely chop 2 tablespoons fennel fronds and reserve. Trim the top and bottom of 1 medium fennel bulb. Quarter, core, and thinly slice. Smash 4 garlic cloves. Halve 1 medium lemon. Thinly slice half the lemon and remove the seeds from the slices; reserve the remaining half. Drain and rinse 2 cans chickpeas.

Step 3

Pour 1 cup olive oil into a 9x13-inch or other 3-quart baking dish. Add 1 1/2 tablespoons harissa paste and 1/2 teaspoon kosher salt; stir to combine. Add the chickpeas, fennel, garlic, lemon slices, and 3 fresh rosemary sprigs. Toss gently to coat everything in the harissa olive oil and arrange into an even layer.

Step 4

Cover tightly with aluminum foil. Bake, stirring halfway through, until the chickpeas are soft but not falling apart, and the mixture is bubbling, about 1 hour total.

Step 5

Uncover and squeeze the juice from the reserved lemon half over the chickpeas and stir to combine. Let cool for 5 minutes. Taste and if you like things spicier, stir in a bit more harissa as desired. Crumble 4 ounces feta cheese over the top, sprinkle with reserved fennel fronds, and serve with crusty bread or over cooked couscous, if desired.