Preheat the oven to 400°F (200°C) and line a baking sheet with parchment paper or foil.
Slice the spaghetti squash lengthwise and scoop out the seeds with a spoon.
Place squash halves cut-side up on the prepared baking sheet, brush or spritz with olive oil, and season with salt and pepper.
Roast for 30 to 35 minutes, until the strands can be easily scraped away from the skin with a fork.
While the squash finishes roasting, melt the butter in a small skillet over medium-low heat, then add the minced garlic and cook 30 seconds until fragrant.
Stir in the lemon juice and zest, add a pinch of salt and the 1/4 teaspoon cracked black pepper, bring to a brief simmer, then remove from heat.
Scrape the cooked squash with a fork into a bowl or onto a plate and gently toss with the warm lemon-butter sauce until evenly coated.
Sprinkle the crumbled feta, toasted sliced almonds, and chopped fresh herbs over the squash and toss lightly to combine, then serve immediately.