Whisk yeast, honey, and 2½ cups lukewarm water in a medium bowl to combine; let sit 5 minutes. (It should foam or at least get creamy; if it doesn't, your yeast is dead. You'll need to buy new yeast and start again. Add flour and salt; mix with a rubber spatula until a shaggy dough forms and no dry streaks remain.

Pour 4 Tbsp, oil into a very large bowl that will fit in your refrigerator. Transfer dough to bowl and turn to coat in oil. Cover with plastic wrap; chill until dough is doubled in size (it should look very bubbly), at least 8 hours and up to 1 day.

Generously butter a 13x9" baking pan (for thicker focaccia that's perfect for sandwiches) or an 18x13" rimmed baking sheet (for thinner, crispier focaccia).

Pour 1 Tbsp. oil into center of pan. Using 2 forks, gather up edges of dough farthest from you and lift up and over into center of dough. Give bowl a quarter turn and repeat process. Repeat 2 more times you want to deflate the dough while you form i into a rough ball). Transfer to prepared pan; pour any oil left in bowl over and turn dough to coat. Let rise, uncovered, in a dry, warm spot (like on top of the fridge or a preheating oven] until doubled in size, at least 1.5 hours and up to 4 hours.

Place a rack in middle of oven; preheat to 450. Poke dough with your finger. It should spring back slowly, leaving a small visible indentation. If it springs bock quickly, it isn't ready and needs to sit longer. Lightly oil your hands. If using baking sheet, gently stretch out dough to fill (you probably won't need to do this if using pan).

Dimple dough all over with your fingers to create very deep depressions (reach all the way to the bottom of the pan). Drizzle with remaining 1 Tbsp. oil; sprinkle with sea salt.

Bake focaccia until puffed and golden brown all over, 20-30 minutes. Melt remaining 4 Tbsp. butter in a small saucepan over medium heat. Remove from heat and grate in 2-4 garlic cloves with a Microplane, depending on your preference. Return to medium heat; cook, stirring often, until garlic is lightly toasted, 30-45 seconds. Brush garlic butter over focaccia and slice as desired to serve.